Durham 425 for 9 dec (Bedingham 118, Raine 71, Lees 70, Gibbon 4-92) and 96 for 2 lead Worcestershire 366 for 5 dec (Haynes 134, Potts 3-110) by 155 runs
Haynes' unbeaten century proved that a strong defence and patience still has a place in a more adventurous era as he defied the Durham attack, reaching three figures from 203 deliveries. The 22-year-old shared a stand of 112 with Gareth Roderick to bring the visitors within 59 runs of Durham's first-innings total before they declared in an attempt to force the issue in the closing stages of the third day.
Joe Leach and Ben Gibbon removed the Durham openers before the close, raising the possibility of a final-day thriller at Chester-le-Street with the home side 155 runs ahead with eight wickets remaining.
Jake Libby had a difficult time at the crease on the second day and his problems persisted into the morning session. Matthew Potts, Ben Raine and Paul Coughlin all beat the bat before Coughlin finally found his outside edge, ending his 87-ball stay for 26. Coughlin thought he had two in two but umpire Hassan Adnan was unmoved for a caught behind shout against Brett D'Oliveira.
Haynes continued his poised innings after the interval, working his way to a deserved half-century, displaying composure to secure the milestone from his 107th delivery with only two boundaries. D'Oliveira was on his way to joining his team-mate, but Matt Kuhnemann removed the left-hander with a simple return chance after finding a leading edge.
Despite the departure of the Worcestershire skipper, Haynes continued to grind down the Durham attack with an impenetrable defence. His knock was one for the purists, blunting the effect of the new ball to further frustrate the home side. He earned his reward by reaching his fourth first-class century, and much like his innings, his celebration was understated with further work to be done to cement Worcestershire's position.
D'Oliveira called his team in after securing their third batting point in a spirited attempt to force a result heading into the final day. Durham lost Michael Jones and Alex Lees cheaply, but David Bedingham and Scott Borthwick stabilised matters to leave the game evenly poised.