Worcestershire 141 for 5 (Kashif 52) lead Derbyshire 130 (Dal 55, Pennington 4-36) by 11 runs
Dillon Pennington's burst with the new ball and Kashif Ali's half-century on his first-class debut earned Worcestershire the initiative on the opening day of the LV=Insurance County Championship match with Derbyshire at New Road.
Pennington reduced Derbyshire to 14 for 5 with four wickets in the space of 18 balls after they had been put into bat and, despite a half-century from Anuj Dal, they were bowled out for 130 in 51.1 overs.
He clearly enjoys bowling against Derbyshire after registering career-best figures of 5 for 32 and a match return of 9 for 76 in the corresponding game last season.
Worcestershire also had initial problems when they launched their reply but Kashif seized his chance following a mountain of runs for the second XI and they closed on 141 for 5 when bad light and then rain halted play at 5.35pm.
Kashif was the first product of the South Asian Cricket Academy to sign a professional contract with a first-class county earlier this season. Three hundreds and four fifties in his last seven knocks for the seconds was a testament to his potential and he reached a 72-ball half-century.
But he became one of several players during the day who surrendered their wicket to careless shots although there was enough movement on a greenish pitch to keep the seamers interested.
Worcestershire handed a debut to Pakistan pace bowler, Mohammad Hasnain. Club captain Brett D'Oliveira was ruled out with a back injury and vice-captain, Jake Libby, led the side while Derbyshire were unchanged from the team which drew with Nottinghamshire.
Libby won an important toss on a green tinged wicket and his bowlers soon justified his decision to put Derbyshire into bat. Joe Leach struck with the last ball of the opening over as Harry Came was plumb lbw to a ball of full length.
But it was Pennington who broke the back of the Derbyshire top order with a superb opening burst of 4-2-3-4. Brooke Guest was bowled offering no shot to a ball angled in and then Wayne Madsen, who began the day needing 32 runs to reach 1,000 for the season, did not reduce that tally as he edged as delivery which nipped away to Josh Baker at fourth slip.
Luis Reece and Hilton Cartwright were both caught behind by Gareth Roderick, after pushing forward to Pennington. Derbyshire captain, Leus du Plooy, opted for an aggressive response and dominated the scoring during a sixth-wicket stand of 39 with Dal.
But Ed Barnard, who is to join Warwickshire on a three-year deal from next season, made further inroads with wickets in successive overs.
Du Plooy, on 38, played with an angled bat at a delivery and gave Baker another catch, this time at third slip, and Mattie McKiernan offered no shot but inside edged onto the stumps. Derbyshire were then 53 for 7 and in danger of being bowled out before lunch but resistance came from Dal and Ben Aitchison
They added 56 in 22 overs before Barnard came back into the attack and had Aitchison nibbling at a delivery which was safely pouched by Roderick. Dal mixed solid defence with some classy shots and two cuts for four off spinner Josh Baker enabled him to complete a 104-ball halfpcentury with eight boundaries.
Hasnain had bowled two threatening spells without any luck but cleaned up the tail in classic fast bowler's fashion as he yorked both Sam Conners and Dal.
Worcestershire also ran into trouble against the new ball and found themselves 23 for 3 in the fifth over. Conners knocked out Libby's off stump with a ball which nipped back and Ed Pollock, having struck Aitchison for six over midwicket, tried to upper cut his next ball and was caught behind.
Taylor Cornall flicked at a leg-side delivery from Conners and also found the gloves of Guest. But the momentum of the game switched into Worcestershire's favour as Jack Haynes and Kashif counter-attacked during a stand of 97 in 18.4 overs.
Haynes reeled off a succession off delightful cover drives and flicks off his legs why Kashif produced a series of back foot punches which pierced the field. The pair took Worcestershire into the lead only to then both surrender their wickets to loose shots.