Season's best for Borthwick
Durham 243 and 67 for 0 lead Worcestershire 205 (Hughes 87, Borthwick 4-37) by 105 runs
Scott Borthwick's best bowling performance of the season enabled Durham to take an unexpected advantage against Worcestershire before rain returned on the third day of their County Championship Division One match at New Road.
The 22-year-old leg-spinner posted impressive figures of 4 for 37 in 15 overs after sparking off the home side's collapse for 205 when he halted Phil Hughes' confident progress to 87 from 136 balls.
From the time the Australian was adjudged leg before, pushing forward to Borthwick's fourth delivery, Worcestershire lost eight for 60 and Durham continued to turn the screw with their openers making 67 without loss.
Mark Stoneman, playing well for the second time in the match, cruised to an unbeaten 41 from 60 balls and Will Smith (20 not out) survived an early chance in the slips as Durham expanded their lead to 105.
With 33 overs still to bowl, they were aiming to build a match-winning position until the rain set in at tea, and now, with only one day left, a positive outcome is less likely in a meeting of two teams without a championship victory.
In all the weather has taken 119 overs out of the game but whatever the outcome there have been some encouraging aspects for Durham.
Following Michael Di Venuto's mid-season retirement, Stoneman has staked his claim for a regular spot and Borthwick took his first real opportunity in this soggy summer.
Having broken into England's one-day set-up in August at the end of last season year, his bowling has almost slipped off the radar on seamer-friendly pitches. In the first half of the campaign, he delivered 17.5 overs in the championship for a solitary wicket taken as long ago as April.
His intervention here came in response to a flying start by Worcestershire. With 45 runs added to the overnight 100 for 2, it was a vital breakthrough when he trapped Hughes after the opener had hit 17 fours.
What came next was a double gift as Moeen Ali and Matt Pardoe both shovelled catches to Michael Richardson on the mid-wicket boundary.
When Borthwick took his fourth wicket, diving forward to hold a return chance to remove James Cameron for 24, the innings was in full retreat.
Jack Shantry did manage to chisel out a batting bonus point with last man Alan Richardson but paceman Chris Rushworth finished the job with 3 for 13 in his post-lunch spell.