Durham 140 for 4 (Lees 52) lead Worcestershire 131 (Carse 4-25, Potts 4-32) by nine runs
Brydon Carse continued his excellent form as he and Matty Potts picked up four wickets apiece to help put Durham in command on day one of the LV= Insurance County Championship match with Worcestershire at New Road.
Carse took his wicket tally to 32 in seven games this summer and ended with 4 for 25 from 13 overs as Worcestershire were dismissed for 131 in 50.3 overs after being put in. He was given excellent support by Potts, who achieved career best figures of 4 for 32 from 12.2 overs.
It was high-quality bowling although they were aided by some undistinguished shots with only Brett D'Oliveira, who batted nearly three hours for an unbeaten 39, offering prolonged resistance.
Opener Alex Leeds ensured Durham capitalised with a fine half-century and Worcestershire were guilty of too many four balls before Josh Tongue claimed two late wickets in a total of 140 for 4.
Worcestershire quickly ran into trouble on an overcast morning and Jake Libby on 13 was caught low down by Lees at backward point of Carse. Potts and Carse then picked up three wickets between them in the space of five balls to reduce the home side to 20 for 4.
Tom Fell managed a single before he looked to work Potts on the leg side and was lbw. Two balls later Gareth Roderick moved across his stumps and was also leg before, and Carse beat the defensive push of Daryl Mitchell as he became another lbw victim.
Ben Raine found the edge of Ross Whiteley's bat and Durham skipper Scott Borthwick made no mistake at second slip. It became 82 for 6 when play resumed after lunch as Potts claimed a third wicket when Ben Cox on 11 went for a drive and edged through to keeper Ned Eckersley.
Ed Barnard collected three boundaries in an over from Potts via two cover drives and an upper cut but two wickets fell in successive overs from Carse. Barnard, on 20, pushed hard at an away swinger and was caught behind. Worcestershire captain Joe Leach departed for a fourth-ball duck when he nicked the same bowler to second slip.
The innings was wrapped up as Tongue went lbw to Raine before Borthwick at second slip held onto a low chance offered by Dillon Pennington off Potts for nought.
Worcestershire needed to strike back early with the new ball and the first bowling change - with Tongue taking over from Leach - brought an immediate reward. Cameron Bancroft was undone by a ball which moved away from him and Fell took a fine low catch at first slip.
Lees completed a 96-ball half century with six boundaries and he and Borthwick put on 69 for the second wicket. But Whiteley came into the attack and in his second over Lees was superbly caught down the leg side by Cox one-handed diving to his right.
Tongue then helped Worcestershire finish the day on a positive note with two wickets in the space of three balls. Borthwick on 42 sliced him to third man where Barnard held onto the chance and then nightwatchman Potts ducked under a delivery but the ball hit his bat and Cox took a sprawling leg side catch.