Worcestershire are facing a battle to preserve their unbeaten record on the final day of the Specsavers County Championship match with Sussex at the 1st Central County Ground despite two sterling contributions from opener Daryl Mitchell.

Worcestershire had to follow on 267 runs behind despite a record breaking double century opening stand between Mitchell (121) and Brett D'Oliveira (80) after losing 10 wickets for 93 runs in 27 overs.

Then in their second innings Mitchell made another 54 before being dismissed – his sixth successive 50 plus score in all competitions – as Worcestershire closed on 124-4 from 43 overs on a pitch where the bounce has become more up and down.

Before the start of play, there was a minutes silence at Hove after the terrorist attack in London yesterday evening to honour those who died and were injured.

Worcestershire, who have won their opening four Championship matches, resumed on 139-0 and Mitchell and D'Oliveira advanced their first innings partnership to 215.

The duo surpassed Worcestershire's previous best opening partnership against Sussex of 181 by CF Walters and HHIH Gibbons at Eastbourne in 1933.

It was their second double hundred partnership in three games after the 243 versus Derbyshire at the 3aaa County Ground.

Mitchell, who was on 85 overnight, went to three figures – off 158 balls with a six and 18 fours – with a single off David Wiese.

D'Oliveira completed his half century off the following ball from 131 deliveries with seven boundaries.

He had a let off on 58 when Will Beer at backward point put down a chance off Wiese and then when on 70 was given out lbw to Vernon Philander but then recalled after the two umpires conferred.

The stand was finally broken as Mitchell on 121 top edged a catch to long leg off Wiese and then D'Oliveira (80) flicked the same bowler off his legs straight into the hands of deep square leg.

Wickets then tumbled at regular intervals with Tom Fell (6) pouched by Chris Jordan at slip off Stiaan van Zyl before lunch which was taken at 228-3.

The second new ball was taken immediately after Joe Clarke smashed Wiese over deep square leg for six.

Clarke (22) pulled Jofra Archer into the hands of deep mid wicket, falling to a good low catch, and Ben Cox (12) edged Philander to slip.

Ross Whiteley (3), making his first Championship appearance of the season, lost his middle stump to Archer and Ed Barnard (22) was lbw to Philander.

Skipper Joe Leach (6) went in the same manner to Archer who also had Jack Shantry (16) caught behind either side of Josh Tongue (0) being caught at backward point off Philander.

Worcestershire followed on 267 behind and D'Oliveira (12) departed to an excellent catch at slip by Jordan off Wiese with 26 on the board.

Fell (22) looked to be finding some form and added 64 in 15.1 overs with Mitchell before he lobbed up a catch to mid on off Jordan.

Clarke brought up the 100 with a cover drive for four off van Zyl and repeated the stroke against Jordan but on 10 he was bowled via the inside edge by Jordan at 109-3.

Mitchell remained resolute and went to his half century off 106 balls with four boundaries before his defiance was ended when lbw to van Zyl on 54.

Tongue was sent in as nightwatchman and saw the County in tandem with Cox through to stumps without any further setbacks.