Sussex started day four on 146 without loss, needing another 203 to avoid an innings defeat, and lost just five wickets as they ended the day on 385 against Nottinghamshire.
Notts remain unbeaten and although the visitors had a strong platform from which to build, Mike Newell's side would have been confident of recording a fifth win of the campaign.
However Chris Nash starred with the bat as he made 162, using up 306 balls, while fellow opener Ed Joyce fell just two runs short of a century.
Luke Wells dug in to make 59 as the hosts failed to take full advantage of their mammoth first-innings total of 520.
Surrey were just as stubborn as Warwickshire, who have a game in hand of Notts, failed to take the 10 wickets required to take them top on day four at Edgbaston.
Openers Zafar Ansari and Rory Burns, aged just 20 and 21, put on 74 for the opening wicket before the latter's stay was ended after he was bowled by Boyd Rankin.
Twenty-one overs were lost to rain as Ansari recorded an unbeaten 83 from 257 balls.
He was well supported by Jason Roy, who was 42 not out, as relegation-threatened Surrey registered what could be three vital points for seeing the day out.
A defiant 10th-wicket stand between Jimmy Adams and Danny Briggs meant Hampshire escaped with a draw against Kent in their LV= County Championship Division Two clash at the Ageas Bowl.
The visitors pushed their first-innings total up to 467 with their final two wickets in the morning session, 175 ahead of the home side's opening effort, before two wickets from Charlie Shreck and one from Mark Davies reduced the home side to 10 for three.
Wickets continued to tumble as James Tredwell destroyed the middle order with three wickets.
The promotion-chasing hosts looked set to lose their third game of the season as they found themselves nine down with 144 on the board and an hour's play left.
However, the duo dug in as opener Adams finished on 85 not out off 255 balls, while Briggs repelled 57 deliveries for his 20.
Fellow promotion aspirants Yorkshire were frustrated by the weather as rain robbed them of a likely victory against Leicestershire at Grace Road.
Sixty overs were lost on the final day as Leicestershire held out for a draw, finishing on 157 for seven, still nine runs behind.
However, the 11 points Yorkshire pocketed took them into second place above Hampshire, while Leicestershire's haul of eight points lifted them off the bottom of the table.
Steve Harmison took three for 52 and Azeem Rafiq two for 18 as Yorkshire pushed for victory.
But a sixth-wicket stand of 67 in 24 overs between Wayne White and Ned Eckersley saw the hosts gain three points for a draw.
In CB40 action, Lancashire pipped Glamorgan to victory and recorded a four-wicket win at Old Trafford.
Gloucestershire posted 184 for seven from their 40 overs, helped by some late blows from Ian Cockbain, who hit 58 from 49 balls.
But Lancashire paced their chase well, and despite losing Karl Brown (60) and Paul Horton (46) with the finishing line in sight, they held on to win with five balls remaining.
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