Lancashire 145 for 6 (Croft 64*, Patel 2-14) beat Birmingham 137 (McCullum 41, Faulkner 3-19) by eight runs
Lancashire gave their NatWest T20 Blast quarter-final hopes a giant boost by beating North Group leaders Birmingham by eight runs at Edgbaston.
It amounted to a happy return to Edgbaston for Warwickshire legend Ashley Giles, now director of cricket at Lancashire, as his side lodged a vital win thanks to Steven Croft's virtuoso all-round performance.
Croft's unbeaten 64 from 51 balls lifted Lancashire to 145 for 6 as they only belatedly shook off scoring shackles imposed by tight bowling led by Jeetan Patel's 4-0-14-2. Then, after Brendon McCullum gave the Bears' reply a spectacular launch with 41 from 25 balls, his departure to that man Croft drained the chase of momentum.
Croft ended with 2 for 16 from his four overs - and pulled off a brilliant catch to boot - as he almost single-handedly sealed two precious points for his team.
Giles said: "It was a fantastic effort from our guys. From the position after ten overs with the bat, Crofty did an incredible job to get us to a total we thought we could defend.
"Even then the way McCullum plays he can take the game away from you after ten overs so all credit to our guys the way that stuck at it in the field and showed no shortage of skill either.
"I told the guys afterwards, as an ex-Warwickshire player and coach, it was the sort of Lancashire performance I expected whenever they came to Edgbaston. They would always fight to the end and make a score out of nothing and that's what they did tonight so I am very happy."
Defeat for Birmingham, meanwhile, leaves them with work still to do to secure a home quarter-final, though they are already guaranteed a top-four spot.
Put in, Lancashire lost openers Ashwell Prince and Liam Livingstone to tamely offered catches to midwicket in the first 19 balls. Rikki Clarke then added the scalp of Alex Davies in an excellent three-over opening spell which cost just seven runs.
Lancashire's batsmen enjoyed no respite against the slower bowlers as the first three overs of spin yielded just 11 runs and another wicket, Karl Brown, lbw to Jeetan Patel's first ball.
At halfway, the Lightning had limped to 44 for 4and, though Croft and Luke Procter shored up the innings with a stand of 41 in 37 balls, their team badly need fireworks in the closing overs. Croft, who hit three sixes and six fours, and James Faulkner (20 off 15 balls) provided a few in a stand of 59 in 34 balls.
The Bears began watchfully, scoring four from the first two overs but, in the third, McCullum climbed into Jordan Clark, lifting the young allrounder for two fours and two sixes. McCullum and Tom Lewis added 40 from 33 balls but when they fell to successive balls in Croft's first over the momentum was punctured.
Croft added a wonderful catch, taken at full stretch at point to dismiss Laurie Evans, to his spectacular night's work and as the required rate escalated, Birmingham needed to find 23 from the last ten balls, which proved beyond a succession of new batsmen from the lower order.