Birmingham 186 for 4 (Hain 79, Bell 57) beat Leicestershire 158 for 9 (Cosgrove 42) by 28 runs
Birmingham put their NatWest t20 Blast campaign back on track after three straight defeats with a 28-run victory over Leicestershire at Edgbaston.
The Bears' 186 for four was built on an opening stand of 125 inside 13 overs by Sam Hain, who scored 79 off 52 deliveries, and Ian Bell, who made a 35-ball 57.
While those two were together the Bears looked set to total over 200 but the Foxes, led by Clint McKay's one for 16 off four overs, fought back well to leave a target around par on a good batting pitch.
But though a string of Foxes batsmen got a start, none played the decisive innings the team needed as they fell short on 158 for nine.
A Bears attack including Keith Barker for the first time in the competition this season kept taking wickets at important times to reassert their qualification bid and extinguish the Foxes'.
After the visitors won the toss, Hain and Bell began in measured fashion, with the latter still to score after two overs, before accelerating past 60 in the sixth over.
The century partnership arrived in the 12th over, both openers having taken advantage of a short boundary to clear the ropes on the off-side.
Hain was first to his half-century, from 36 balls, Bell's following from 32, but the latter's dismissal after striking four fours and four sixes in his 57, edging Rob Taylor behind, signalled a sharp drop in momentum.
Bell's wicket was quickly followed by that of Matt Wade, on his home debut, as the Australian fell lbw to his countryman McKay for five.
When Hain sought another six - his third of the innings to go with nine fours - off Cameron Delport but found only the hands of Ben Raine at deep extra-cover, three wickets had fallen for 26 runs in 18 balls.
Laurie Evans perished in similar fashion to Hain and although Rikki Clarke (24 not out) landed a couple of hefty blows, a skilful final over from McKay sent the Foxes into the mid-innings break in perky mood.
The Foxes reply started briskly with Mark Cosgrove and Mark Pettini adding 36 in 27 balls before the latter pulled Oliver Hannon-Dalby to Jeetan Patel at deep mid-wicket.
Delport's 18-ball 20 included an audacious reverse-swept six off Josh Poysden but the South African perished attempting a repeat off Ateeq Javid.
As the required run-rate rose, greater risks had to be taken. Cosgrove (42 from 29 balls) hoisted Patel to long off, Lewis Hill charged the same bowler, missed, and was adroitly stumped by Wade and when Farhaan Behardien lifted Clarke to long-off all that remained in the Foxes' locker was some futile swishing.