Leicestershire 149 for 5 (Ackermann 47*) beat Worcestershire 148 for 8 (Cox 51, McKay 5-11) by five wickets
Clint McKay returned the best ever figures by a Leicestershire bowler in domestic T20 as they secured a five-wicket win over Worcestershire Rapids at New Road.
The Australian finished with 5-11 from his four overs, surpassing the 5-13 by Andrew McDonald versus Nottinghamshire at Trent Bridge in 2010. It was also McKay's personal best in the short format of the game as the Rapids were restricted to 148 for 8.
McKay said: "The funny thing about it is I've actually been feeling quite sick all day so I wasn't particularly looking forward to playing tonight. But it was the same as usual, the same preparation, and I try and bowl the best ball everytime. Tonight I was very lucky and other days you bowl nicely and it doesn't quite work out for you."
Colin Ackerman's unbeaten 47 off 36 balls then enabled Leicestershire to overcome a mid-innings wobble as they reached their target with nine balls to spare.
Leicestershire have now triumphed in their opening two games in a competition they have won three times whilst the Rapids have slumped to back-to-back defeats - both at New Road.
Worcestershire opted to bat first on the same pitch as used for the previous T20 Blast game against Birmingham Bears but lost two wickets inside the opening two overs from McKay. Joe Clarke, who was again promoted to open, attempted a cut and was caught at first slip and then Brett D'Oliveira nicked through to keeper Luke Ronchi.
Ben Cox, who hit a career best 124 in the County Championship match with Gloucestershire at Cheltenham this week, again looked in good form and struck three fours and a six in Gavin Griffiths second over. Cox and Daryl Mitchell added 56 in seven overs and in the process the latter became Worcestershire's highest ever run-scorer in T20 cricket, surpassing the 1,890 total of Moeen Ali.
But on 31, Mitchell swept Cameron Delport into the hands of short fine leg and skipper Joe Leach failed to trouble the scorers before being yorked by Griffiths.
Cox went to his half century off 35 balls with five fours and a six but lofted the next delivery from Callum Parkinson straight to long-on.
McKay returned to the firing line and struck twice in two balls with Ross Whiteley holing out to long off and Mitchell Santner pouched on the midwicket boundary. The 34-year-old completed his haul in the final over as Ed Barnard also fell in the deep.
When Leicestershire replied, New Zealand keeper Ronchi showed immediate aggressive intent as he struck the first three deliveries of the innings from Leach for boundaries. Australian allrounder John Hastings suffered the same treatment in his first over, this time from Delport.
Black Caps spinner Santner broke the stand on 41 by bowling Delport and the first ball from Mitchell accounted for Ronchi in the same manner at 61 for 2 in the seventh over.
D'Oliveira's introduction into the attack bore instant reward with Foxes skipper Mark Cosgrove and Ned Eckersley falling at long-on and cover respectively.
There was still work to do for the visitors when Lewis Hill was stumped to give Santner a second success and 40 were required from the final five overs. But Ackerman and Tom Wells (31 not out) ensured there were no more alarms for Leicestershire.