Brett D'Oliveira said his best day in first class cricket will count for nothing unless Worcestershire continue where they have left off and force victory against Durham on the final day of the LV = County Championship match at the ICG Emirates.
Spinner D'Oliveira grabbed the opportunity to have a longer bowl after the departure of Saeed Ajmal by returning the first five wicket haul of his career.
He finished with figures of 5-48 from 15 overs as Durham were dismissed for 277 to give Worcestershire a first innings lead of 73.
They extended that to 115 by the close with D'Oliveira scoring an unbeaten 32 not out and skipper Daryl Mitchell 10 not out in reaching 42-0.
D'Oliveira said: "It's been my best day in first-class cricket, but it won't mean anything unless we push on and win.
"Not having Saeed Ajmal gave me more chance to bowl, but he helped me a lot with both technical stuff and the mental side or how to read a batsman.
"It's great to get my first five-for. The odd one turned and it was just a matter of staying patient and waiting for the batsmen to make mistakes."
Durham's Scott Borthwick, who made his tenth championship half-century of the season said: "It's good that I've been more consistent but massively frustrating that I haven't gone on to make big hundreds.
"I hope I've put us in a good position and we will back ourselves to chase down whatever target they set us."