FULL-TIME: Sheff Utd 1-0 Yeovil. The Blades take a narrow lead into Monday's second leg.
Four minutes have been added - one left for Yeovil to save this game.
SHEFF UTD sub: Elliott Whithouse replaces Porter.
Webster volley on the turn brilliantly saved by the keeper.
Another penalty shout for Yeovil as the ball hits Harry Maguire's knee and then his hand. Purely unintentional.
Fortunately for Stech, the corner is easily dealt with and Yeovil launch a bid to snatch a draw.
Stech gets a clearance from inside the Sheff Utd half all wrong and carries it out of play for a corner to the hosts. Bizarre from the visiting keeper.
Thoughts on who is likely to reach Wembley based upon tonight's match? Tweet us your views.
Yeovil pressing but it's more of a high ball onslaught rather than composed approach play.
It's been a slightly better second half but not really a classic. It's been tight which is perhaps to be expected given how close the two teams were in the league table.
Yeovil pushing hard now but time is running out. Just eight minutes left.
PENALTY SHOUT for YEOVIL. Ayling's attempted cross hits the hand of McFadzean, but the referee says no penalty.
Westlake whips it in but it is eventually cleared under pressure.
Free-kick to Sheff Utd on the right in a good position.
Remember there are is no away goals rule in the play offs. So even if the score remained the same and Sheff Utd scored at Huish Park it wouldn't be a disaster from that point of view.
Time running out for Yeovil but a 1-0 deficit would not be something they couldn't turn around on home turf.
Doyle wins the ball off Balanta but arrows a shot high and into the crowd.
SHEFF UTD sub: Joe Ironside on for Kitson.
A corner for Yeovil comes to nothing.
YEOVIL sub: Hayter replaced by Angelo Balanta.
Ayling finds space on the right and crosses to Madden at the far post, but his header down into the ground allows Sheff united to clear from under the crossbar.
Murphy picks up the ball on the left of the area, drops his shoulder and curls a great effort just past the upright. The hosts are pushing.
And now it's Sheff Utd's turn to dominate. Can they get a second goal to take into Monday's second leg?
McFadzean tricks his way beyond McAllister on the right wing, cuts into the area and hammers in a shot that Stech does well to push to safety.
Play has been halted for McFadzean to receive the magic sponge.
Kitson chips a high cross into McFadzean who can't control his header. The youngster appears to take a knock off McAllister and requires treatment.
Luke Ayling shoots from distance but it's well wide.
Hayter takes advantage of a slip on the left and plays a poor cross into Madden who can't get his shot away due to the height of the pass. Wasted opportunity for the away team.
Yeovil beginning to dominate possession as they search for an equaliser.
Michael Doyle booked.
Almost an hour gone? Full-time score predictions? Tweet us your views.
Murphy picks up the ball on the left and races across the face of the area before firing in a shot that Stech does well to gather at the first attempt.
GOAL! .... But it's OFFSIDE! Hayter gets in behind the defence and clips the ball beyond the keeper - but he mistimed his run and the flag was correctly raised. Still 1-0 to Sheff Utd.
The breakthrough has sparked a decent response out of Yeovil. Both teams seem to have a bit more space in attack which can only bode well for the remainder of the half.
The goal was the Blades' first in over five hours of football.
Edward Upson lines one up from distance and forces a very unconvincing save out of George Long. The keeper was lucky no one was following up for the away side.
Madden escapes his marker down the left and fizzes in a dangerous ball that is well defended at the near post.
Half chance for Yeovil. A cross from the left falls for Dawson but he fails to control it and Sheff Utd are able to hack to safety.
Reports suggesting Robson has had to go to hospital with a suspected broken rib.
It's a poor delivery and the hosts clear their lines.
Yeovil look to respond immediately and win a corner.
That was the 19-year-old's first ever goal for the Blades. Not a bad time to get it!
GOAL! 1-0 to Sheff Utd. Sensational start to the second period for the Blades. A cross from the left finds its way through to McFadzean who sees his deflected effort fly into the net.
KICK OFF! Sheff Utd restart the match.
HALF-TIME: A poor first half ends goalless after Sheffield United missed a couple of decent early chances.
Two minutes added.
It's been a dour first period but there have been chances for Sheff United. But Yeovil could well pinch this on the break in the second period.
Kitson gets a header on goal from the resultant free-kick but is penalised for pushing.
McAlllister booked for a nasty challenge. Could easily have been red.
Wonderful break by Yeovil ends with Madden teeing up Joe Edwards but his shot is brilliantly blocked on the edge of the box.
Neither side seem capable of keeping the ball for more than three or four passes at the moment. It looks set to be goalless at the break...
Kitson booked for Sheff Utd.
Can someone find a spark to set this game alight? Tweet us your views so far.
Sheff United's best hope seems to be down that right flank. Most of their best moves have come down that side.
Chance for Yeovil! But Kevin Dawson drags wide of the far post after good hold up play by Hayter.
The stoppage for the injury to Robson really hasn't helped this game. There's no flow or pattern to it and both sides are now toiling a bit.
Sheff Utd may be ahead on attempts on goal - but it's 0-0 for attempts on TARGET. That stat sums up the first half an hour or so.
SHEFF UTD sub: Robson replaced by Callum McFadzean.
He's still down and play has been stopped.
Robson receiving treatment for a knock he took to the ribs. It looks like he'll have to go off.
Attempts on goal: Sheff Utd 4-1 Yeovil.
They've already been stung by Madden this season and you could see a similar result tonight unless someone finds their shooting boots.
The Blades have been lacking a cutting edge of late and you can see why as they have missed some good opportunities already tonight.
Jamie Murphy flashes a shot way over the top from 10 yards after a free-kick into the area caused hoavoc amongst the Yeovil defence.
Porter shows real pace to make something out of nothing on the left wing. The Blades fail to find the final pass though and it eventually ends with an offside against Kitson. Good organisation and pressing by Yeovil.
Gary Johnson will be delighted with the first 20 minutes. His team haven't conceded despite some early scares and are now finding their feet.
It's becoming more and more scrappy out there. The game needs a goal.
Yeovil starting to settle now after a shaky start.
A free-kick on the right allows Sheff Utd to lift one into the area but it's too close to Marek Stech who gathers with ease.
McDonald is overly casual trying to tidy up in defence and leaves George Long with it all to do with his back pass. Fortunately for the Blades, the keeper is quick on his feet and is able to hammer the ball to safety under pressure.
Jamie McAllister whips one into the mixer but the pushing and shoving in the ruck of players leads to a free-kick to the hosts.
But here come the Glovers on a rare foray forward.... Corner ball!
The Blades have carved Yeovil open on a few occasions already but their profligacy means we are still goalless.
Robson delivers the resultant kick towards Porter who flashes a header past the upright.
Penalty shout for the hosts. Kevin McDonald hoists a ball high into sky inside the area and as challenges for a header he's shoved over by Dan Burn. He screams at the ref who points for a corner.
Sheffield United on top here but no real efforts on goal as of yet.
STAT: The Glovers' only previous experience of the play-offs was at this level back in 2007. They saw off Nottingham Forest 5-4 on aggregate in the semi-finals, but were then beaten 2-0 by Blackpool in the final.
Want to know the results between the two sides in League One this season? Well, Yeovil won 2-0 at Bramall Lane back in January, thanks to a Paddy Madden double. However, the Blades had won the trip to Huish Park 1-0 three months earlier, courtesy of a Neill Collins goal.
Free-kick to Sheff Utd 30 yards from goal.... Robson steps up and curls a superb effort inches past the right-hand post. The Blades are on top early doors.
However, Swindon have been promoted through the play-offs in three of their six attempts.
Sheffield United and Brentford have both been beaten in the play-offs on six occasions, while Yeovil lost in the final in their only previous attempt.
STAT: Of the four teams involved in the play-offs, only one has ever gone up via this route.
Another chance for the Blades. Robson curls a cross in from the right for Kitson but he gets his header all wrong and Yeovil survive when they could easily have been picking the ball out of their net.
And the winners of this tie will then face Swindon or Brentford in the final at Wembley on 19 May.
It'll be a quick turnaround for the second leg with United travelling to Huish Park as early as Monday. That's the play-offs for you. No time to take a breather.
Porter beats the offside trap and plays in Dave Kitson on the right-side of the area. The forward sees Jamie Murphy unmarked at the back post, but his clipped cross is overhit. A great opening goes to waste for the hosts.
KICK OFF! Yeovil get the game underway.
Sheffield United line up with a 4-4-2 formation and are boosted by the news that striker Chris Porter and midfielder Barry Robson have returned to the starting XI. Yeovil are also deploying a 4-4-2 formation with League One's top scorer, Paddy Madden paired with James Hayter in attack.
STAT: This was Yeovil's 10th season as a Football League club and they achieved their highest ever finish (fourth in League One).
STAT: This is only the fifth meeting between these two teams. Sheffield United have won three and lost one of the previous four - all League One matches.
Meanwhile, Yeovil boss Gary Johnson is hoping the travelling support can inspire his side to get a result. He said: "I'm just pleased we are here in the play-offs and I'm pleased we've got the home leg second. People know that we need them up in Sheffield. Sometimes if you can get a couple of thousand of your fans, even if they are in a group of 30,000 home fans, they can make a noise because they are up for it. Anything like that helps and certainly the support on the day will be fantastic."
More from Morgan: "It would be a massive achievement if we got promoted. I was lucky enough to come onto the coaching staff two years ago and we've worked hard to achieve promotion. When you lose a play-off final you sometimes see teams drift away but we've competed at the top end of the division all season. We've lost vital players, we've had things cut back and we have adapted and kept going. That is credit to everyone involved here."
STAT: Sheff Utd's Caretaker boss, Morgan took over at Bramall Lane last month after the departure of Danny Wilson. The 35-year-old has been with the Blades since 2003 and captained the club to promotion to the Premier League in 2006.
Teams - SHEFF UNITED: Long, Westlake, Maguire, Hill, Doyle, Porter, McDonald, Kitson, Collins, Robson, Murphy... Subs: Coyne, Higginbottom, Chapell, Ironside, McFadzean, Whitehouse, Barry. /// YEOVIL: Stech, Ayling, Webster, Burn, McAllister, Dawson, Upson, Edwards, Foley, Madden, Hayter... Subs: Stewart, Hinds, Blizzard, Williams, Maksimenko, Young, Balanta.
The Blades came third with 90 points last season, but lost to Huddersfield on penalties in the play-off final. As a consequence, Sheff Utd caretaker boss, Chris Morgan reckons his side are underdogs this year. He said: "I think there will be lower expectations. Maybe that's good that we're not the team finishing third. I don't think many people would have us down as favourites. We've come into the play-offs on the back of a few results where we've not been at our best. But it all changes now."
Yeovil's Patrick Madden was League One's leading scorer with 23 goals this season. Nick Blackman and Dave Kitson were the Blades' main source of goals with 11 apiece.
So, which team is going to take a step towards Wembley tonight? Get involved and share your pre-match views on the comments below or on Twitter.
In the final standings Yeovil (fourth) finished two points ahead of the Blades (fifth).
Good evening and welcome to our live matchcast of the League One play-off semi-final, first leg between Sheffield United and Yeovil at Bramall Lane.