GAME, SET AND MATCH! - FEDERER 7-6 5-7 6-1 ZVEREV. The world No.3 eventually tames a star-in-the-making after a two-hour and 11 minute battle. Federer breaks again as Zverev double faults on match point and it means the Swiss has now qualified for the semi final. Zverev will meet Jack Sock in a win or bust clash on Thursday.
Roger Federer - Alexander Zverev
ATP World Tour Finals - 15 November 2017
World Tour Finals – Follow the Tennis match between Roger Federer and Alexander Zverev live with Eurosport. The match starts at 04:00 on 15 November 2017. Our live coverage lets you follow all the key moments as they happen.
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FEDERER 7-6 5-7 5-1 ZVEREV. That will surely be it now. Federer fends off another break point as both players produce some magical moments. An audacious lob pegs FedEx back to deuce, but the Maestro eventually comes good with a crunching forehand winner to move within one of victory.
BREAK! - FEDERER 7-6 5-7 4-1 ZVEREV. Disaster for Sascha. He marauds to a 40-0 lead - and then capitulates. Fed earns a chance at the double break and gets it when Zverev slaps a forehand into the net off some devilish Swiss slice.
FEDERER 7-6 5-7 3-1 ZVEREV. Federer looks determined now. He doesn't want to let another break slip and consolidates to love.
BREAK! - FEDERER 7-6 5-7 2-1 ZVEREV. The watching world have been lauding the pretender - but it's the veteran superstar who steps on the gas and makes the first breakthrough of the set. Fed lets out a cry of delight and indulges in a fist pump. He wanted Zverev to see that too.
FEDERER 7-6 5-7 1-1 ZVEREV. Federer finds a big second serve to easily come through his opening service game of this set unscathed. No lingering dismay is likely with the Swiss. He's been and done it all during his career. This is now a one-set match.
FEDERER 7-6 5-7 0-1 ZVEREV. Federer's radar is definitely malfunctioning, but it may be partly down to his concern over Zverev's impressive form. The German holds to 30 to earn the scoreboard advantage and maintain his bid to pull off a surprise.
SET! - FEDERER 7-6 5-7 ZVEREV. Wow! Zverev comes out all guns blazing and Federer surprisingly folds. The Swiss offers up three set points and shanks one wide of the left tramlines he is facing on the final one. All square - we are heading to a decider!
FEDERER 7-6 5-6 ZVEREV. Federer muttering in frustration. Not something you see that often. He's nowhere near top gear, but Zverev isn't letting him get there either. A sizzling backhand down the line proves too good as the German guarantees himself the minimum of a tie break.
FEDERER 7-6 5-5 ZVEREV. Same again from Fed. A lovely drop volley clinches a smart love hold under pressure. All square at the business end. Are we heading for another tie break?
FEDERER 7-6 4-5 ZVEREV. Sascha is loving the stage and the challenge. He's making Federer look like an average returner at times, which is rather impressive.
FEDERER 7-6 4-4 ZVEREV. Federer knows he's in a real battle here. A strange lob attempt is despatched with relish by Zverev to earn a break point. Federer responds and comes through from deuce with a sublime drop volley.
FEDERER 7-6 3-4 ZVEREV. This has been a high calibre battle. Zverev living up to the hype that he's going to be a Slam champion of the future. Once again he breezes through an excellent hold.
FEDERER 7-6 3-3 ZVEREV. Federer keeps it simple by keeping his serves away from Zverev's weapon - the backhand. It works well as he halts the youngster's surge with a hold to 15.
FEDERER 7-6 2-3 ZVEREV. It's three in a row as Sascha rattles through after an opening double fault. He's got his nose in front. Don't think many were expecting this at 2-0 down and having suffered such a devastating collapse in the tie break.
BREAK! - FEDERER 7-6 2-2 ZVEREV. Federer is his own worst enemy as a rush of double faults see 30-0 turn into break point alarm bells. The Swiss saves two, but can't deny the German on the third as he passes the Swiss at the net to level the set. That's a fabulous response from the No.3 seed.
FEDERER 7-6 2-1 ZVEREV. The No.3 seed stops the rot and gets himself on the board for the loss of one point.
FEDERER 7-6 2-0 ZVEREV. The six-time winner of this title consolidates to love with a real flourish. Zverev has lost some of his verve right now. He needs to find it in the next minute or so, or Federer will run away with this set.
BREAK! - FEDERER 7-6 1-0 ZVEREV. Sascha's frustration and disappointment is tangible. He can't clear the cobwebs quick enough and a double fault offers up triple break point for Federer. The German saves one, but slaps a weak forehand into the net on the next. FedEx has the scent now and that usually only means one thing on a tennis court. Success.
SET! - FEDERER 7-6 ZVEREV. A cracking set of tennis ends with Federer roaring back from 0-4 down in the tie break to triumph 8-6 in 55 minutes. It's tough on Zverev, who competed valiantly and had set point while attacking a second serve. Federer showing just why he is such a champion, playing the big points the best.
TB LATEST: Zverev leads 4-2 at the change of ends, but he was 4-0 up. Is Fed going to sneak it?
FEDERER 6-6 ZVEREV. Massive hold. It's the game of the match so far. Both produce some moments of magic, but it's Zverev who drags himself over the line to earn a tie break. Federer had two set points, but couldn't convert as one unlucky net cord in particular allowed Zverev to survive.
FEDERER 6-5 ZVEREV. Super defence from Federer. The Swiss comes under attack as 30-0 slips away under attack from Zverev's crushing backhand. The world No.2 uses smart slice to perfection wriggle through a mini test and pile the pressure back on the youngster's shoulders.
FEDERER 5-5 ZVEREV. Too good. Zverev refuses to give the Maestro a look-in with more aggressive serving right out of the top drawer.
FEDERER 5-4 ZVEREV. Federer responds with his own perfect hold in just over a minute! A bit of added pressure for the No.3 seed now...
FEDERER 4-4 ZVEREV. More fine work from Zverev. His serve has great rhythm and power so far tonight, but he's mixing it up with some nice touches too. A wand of a crosscourt backhand and a deep volley at the net see him claim another hold to love.
FEDERER 4-3 ZVEREV. Federer produces a lovely dropshot on his way to another simple hold to 15 as the games begin to whistle by. The 19-time Grand Slam champion is exploiting the vast space being left in the forecourt by the baseline hugging Zverev.
FEDERER 3-3 ZVEREV. That's rather impressive from Zverev. Over 70 per cent of his first serves are landing in and it helps him along to a tasty love hold.
FEDERER 3-2 ZVEREV. 'Come on!' Federer pumping himself up as he hits back from 15-30 to stand firm. The Swiss will be well aware he's red-hot favourite to win the tournament, never mind the group, and Zverev is definitely one of the few here in London who could upset him.
FEDERER 2-2 ZVEREV. Sascha made to work a little bit harder, but serves well to hold to 15. Many observers were looking forward to this one and so far they won't have been disappointed.
FEDERER 2-1 ZVEREV. Lightning quick! Federer romps through a splendid love hold.
FEDERER 1-1 ZVEREV. The young German follows suit with a poor opening on serve before rallying to get on the board. He battles back from 0-30 but Federer presses him to deuce and snares a break point. A couple of aces and a super drive volley turn it around in magnificent fashion as this one begins to warm up nicely.
FEDERER 1-0 ZVEREV. A sluggish start from FedEx. A couple of uncharacteristic errors into the net tee Zverez up for triple break point. The Swiss rallies with some smart serving to save all three before a sweet backhand clinches a significant hold.
Federer won the toss and chose to serve first. Here we go....
PREVIOUSLY: Zverev edged out Marin Cilic in a tight contest on Sunday night. He'll need to raise his game to beat Federer, but he has done it before and is the only man amongst this tournament's field to have defeated the Swiss in 2017.
HEAD-TO-HEAD: This the fifth meeting and it's currently 2-2. Zverev lifted the Masters 1000 title in Canada when he beat Federer 6-3 6-4 in their most recent meeting, while the Swiss was the champion when they met in Halle.
Hello and welcome to LIVE updates of the Nitto World Tour finals round robin clash between Roger Federer and Alexander Zverev. A victory for the Swiss legend will see him book a place in the semi finals with a match to spare - but can the young pretender provide a twist and upset the Maestro?