Worcestershire fought back strongly with the ball and some superb fielding during the final session as 17 wickets fell on day one of the LV=Insurance County Championship fixture with Nottinghamshire at Trent Bridge.
They were initially on the receiving end of an inspired performance by Nottinghamshire pace bowler Dane Paterson who returned career-best figures of 8-52.
He fully exploited extremely helpful conditions as Worcestershire were dismissed for 159 after being put in.
Jack Haynes (37) and Ed Pollock (31) were their main contributors, but it was a challenge for all the batters on a green pitch under cloudy skies.
But Worcestershire hauled themselves back into contention with a flurry of wickets.
Keeper Ben Cox produced two outstanding catches to dismiss Haseeb Hameed and Joe Clarke, while Jake Libby and Josh Baker excelled in the field as Ben Slater and Liam Patterson-White were run out.
Nottinghamshire ended on 203-7, and the visitors will be looking to make further inroads first thing tomorrow morning in what are likely to be similar conditions on day two.
Worcestershire made one enforced change to their line-up with all-rounder Joe Leach, in excellent form this season, ruled out through illness.
Finch came into the side for his first senior appearance of the campaign.
Openers Jake Libby and Pollock made a positive start against the new ball attack of Luke Fletcher and Stuart Broad.
Libby pulled Broad for the first boundary, and Pollock leg glanced and cut Fletcher for four.
But there was plenty of encouragement for the bowlers, and Libby (15) was caught behind off a Broad delivery which bounced and seamed away from him.
Pollock continued to attack in the same manner that brought him a century against Leicestershire and 77 off 74 balls against Sussex.
He swung Fletcher over the long deep backward square boundary for a huge six and raced onto 31 from 32 balls.
But Paterson came into the attack and struck with his first delivery as Pollock pushed forward and nicked to third slip.
It was the start of an inspired spell by the 33-year-old, who ended with career-best figures of 8-52.
Azhar Ali (6) and Club Captain, Brett D’Oliveira (10), were both caught behind and Ed Barnard (8) tried to leave a delivery and inside-edged onto his stumps.
It was D’Oliveira’s first dismissal of the season, and he currently has a batting average of 304 this season.
Haynes played some fine strokes, forcing Paterson off the back foot square of the wicket for four and cover driving the same bowler to the fence.
He was unbeaten on 33 out of 114-5 at lunch, but Paterson continued to make inroads on the resumption.
Ben Cox (2) went lbw, Haynes was undone by a ball which nipped away and edged to the keeper, Josh Baker (12) was caught off a leading edge at mid on and Charlie Morris (1) was bowled by a ball which kept low.
Pennington (18) provided Moores with his fifth catch of the innings off Luke Fletcher.
When Nottinghamshire batted, Morris bowled a testing opening spell with Pennington stepping up to share the new ball in Leach’s absence.
But the home side took advantage of some loose deliveries in the helpful conditions, and Hameed reached a 54 ball fifty with 11 fours.
It needed a fine piece of fielding by Libby to break the opening stand with 70 on the board.
Hameed played Finch through the covers for what looked like a boundary, but Libby produced some great work just inside the ropes, and his throw found the alert Cox, who broke the stumps with Ben Slater (24) out of his ground.
Cox then produced a superb catch low to his right to dismiss Hameed (53) off Finch.
Ben Duckett on 11 survived a head-high chance at slip off Baker’s second delivery.
He went onto make 50 from 39 balls with eight fours before being caught behind off Pennington.
Cox excelled again by taking a chance in front of first slip offered by Clarke (18) off Barnard.
Worcestershire were now on a roll, and Steven Mullaney (7) and Lyndon James (19) fell in successive overs to catches by Haynes at second slip off Morris and Barnard, respectively.
Baker then ran out Patterson-White (0) with a direct hit from cover point after Tom Moores had called him through for a single.