Worcestershire will go into the third day against Durham needing four more wickets to confirm their promotion to Division One of the Specsavers County Championship.
Having started their final fixture at New Road requiring six points to be sure of a top-two position, they were halfway to their target when another show of lower-order batting strength took them to a total of 335.
Confirmation could also come from events at Leicester, where Northamptonshire closed on 199 for eight and must reach at least 350 to have any hope of overtaking leaders Worcestershire.
India Test star Ravichandran Ashwin, with 82 for his first half-century in a four-match stint in the championship, and all-rounder Ed Barnard, with a career-best 75, were the leading players as the last five wickets added 203.
Worcestershire’s bowlers then began the task of taking nine wickets in 110 overs to secure a fifth promotion in 11 years under director of cricket Steve Rhodes.
Two for Josh Tongue, making 47 for the season, and one for skipper Joe Leach secured a fourth point before Paul Collingwood and Graham Clark dug in for 18 overs in a stand of 76.
Collingwood was bowled for 27 attempting to cut Ashwin but Clark hit three sixes in reaching 60 from 65 balls before he was caught and bowled by Leach.
Durham, bidding farewell to Lancashire-bound pair Graham Onions and Keaton Jennings, closed at 142-5, still 193 behind.
Jennings was out for nine, caught behind off Tongue, after Onions had Leach caught in the gully and bowled Tongue to complete a return of four for 68.
Although the pitch took some spin, 18-year-old Liam Trevaskis capturing his first Championship wicket by trapping Ashwin leg before, Durham were unable to force home their position after a useful morning’s work.
Clarke was a comforting presence for Worcestershire in a tricky first hour. The England Lions batsman resumed with 46 in an overnight 90 for three and quickly completed his half-century.
However, he progressed only as far as 65 before Onions drew him into a drive outside the off stump and saw the edge neatly taken by Collingwood at first slip.
George Rhodes went for nine, lbw playing back to off-spinner Ryan Pringle, and Ben Cox, after making 30 out of a stand of 66 with Ashwin, was bowled by Cameron Steel just before lunch.
With Worcestershire on 198-6, they needed a big effort to secure their initial objective of a 300-plus total. The impetus came from Ashwin and was brilliantly built on by Barnard with his fifth championship half-century of the summer.
Three sixes, one of which smashed a window in the entrance to an on-site cafe, backed up six fours by a fast-maturing 21-year-old who has scored 580 Championship runs and taken more than 40 wickets this season.
When joined by last man Pat Brown, he made one last effort to take his side closer to 350 but was bowled when aiming an over-ambitious shot at Mark Wood.
Durham batsman Jennings spoke of his decision move on to Lancashire next summer.
He said: “I’ve had plenty of soul searching in the last few weeks and a few tough conversations, a few very good conversations as well.
“I’m very pleased to have made a call and I was very thankful with the backing and the support I have got from the coaching staff and management at Durham and Lancashire.
“I am looking forward to see what the future holds and I’m really excited.”
Worcestershire assistant coach, Matt Mason, said: “The wicket hasn’t played as we expected. It has seamed a lot with both new balls today.
“Ashwin, Ben Cox and Ed Barnard all did a fantastic job in getting us our total and then I thought the bowlers hit great areas.
“We weren’t focusing too much on what is going on elsewhere.
“We haven’t talked about a what points we need , we just wanted to win the game, knowing that if we played the game like we have done all year, that would be the best way to approach it.
“That’s why we have won the games we have done.”