Sussex 202 and 144 for 3 (van Zyl 66*) need a further 68 to beat Durham 224 and 189 (Harte 74, Wiese 5-43)
Sussex were in prime position to claim their first Specsavers Championship Division Two win of the season after day three at Emirates Riverside, requiring another 68 runs to beat Durham.
David Wiese put his team in contention by producing a fine spell of bowling to claim five wickets, dismissing the home side for 189 in their second innings. Gareth Harte scored 74 vital runs for the north-east outfit to set a decent chase of 212 for the visitors.
Stiaan van Zyl dropped anchor after Durham made early inroads. The South African scored an unbeaten half-century to put his team within sight of victory at the close, leaving the home side in need of a dramatic turnaround on day four.
Durham began poorly as Alex Lees fell to his first delivery of the morning, edging behind to Ben Brown off Wiese. It would be theme of the opening session as the visitors were able to take command. Harte should have followed Lees back to the pavilion, but he was dropped on 13 by Laurie Evans at midwicket - it would prove to be costly one for Sussex.
However, Mir Hamza made further inroads, claiming the vital wicket of Cameron Bancroft. The Australia international played a loose drive and was caught behind for 22, while Jack Burnham was pinned lbw for 5. At 70 for 4, Durham were in need of a partnership to stem the tide. Ned Eckersley joined Harte at the crease and the duo were able to put together a stand of 35.
Eckersley notched back-to-back boundaries off the medium pace of Tom Haines, but then slapped the next ball straight to Evans. His dismissal sparked a collapse as the hosts lost three wickets for one run. Liam Trevasksis and Ben Raine were removed by Wiese in the space of three deliveries, leaving Durham in trouble at 106 for 7, with a lead of only 128.
Durham followed the example of Sussex's lower order from day two, with some defiance of their own. James Weighell combined with Harte to add 44 for the eighth wicket. Wiese was the key man for the visitors again to break their stand before accounting for the scalp of Matt Salisbury, claiming his fifth wicket of the innings.
Harte continued his impressive knock, reaching his second fifty of the campaign from 113 deliveries, his two boundaries highlighting a patient approach on a slow pitch. He added 37 runs for the final wicket with Rushworth to take Durham's lead over the 200-run mark before Chris Jordan ended the innings, as Harte finished unbeaten.
Sussex lost early wickets in their chase, Phil Salt and Haines out cheaply to Rushworth and Raine respectively. Luke Wells and Van Zyl formed a partnership to see off the threat of the new ball. Both batsmen applied themselves well at the crease, taking few risks with their shot selection.
Wells was continuing to be a thorn in the side of the hosts, but Salisbury struck to break the partnership for 83. Van Zyl continued his knock, reaching his fifty from 89 balls and putting the pressure on Durham.