Derbyshire 174 for 5 (Madsen 71*, Wood 39) beat Birmingham 157 for 9 (Mousley 36, Chappell 3-32, Zaman -34) by 17 runs
Wayne Madsen's remarkable run in the Vitality Blast continued as the Derbyshire Falcons ended Birmingham Bears' winning streak in the North Group with a 17-run victory at Derby.
Madsen came into the game on the back of three fifties and a hundred and delivered another white-ball masterclass with an unbeaten 71 off 52 balls out of 174 for 5.
Tom Wood hammered 39 from 19 as he and Madsen plundered 79 off 41 balls with Glenn Maxwell taking 2 for 19 in four overs.
The Bears' hopes of equalling their best ever start in the T20 with a fifth victory quickly faded as they slipped to 45 for 4 in the powerplay with Moeen Ali falling for 16.
Maxwell briefly threatened with 29 off 22 balls before Dan Mousley and Ed Barnard added 49 off 30 but the Bears came up short on 157 for 9 with Zak Chappell taking 3 for 32 and Zaman Khan 3 for 34.
Moeen, playing his first game for his home county for 17 years, had elected to bowl first on a sunny evening at the Incora County Ground.
Luis Reece swung Maxwell for six before pulling Henry Brookes into the hands of deep square which brought in the prolific Madsen who cut his first ball for four.
He drilled Craig Miles past mid on for another four as the Falcons ended the powerplay on 43 for 1 and Haider Ali greeted Jake Lintott by launching him over the ropes at wide long on.
His attempt to do the same to Maxwell was pouched by Mousley at deep midwicket but Madsen was the wicket the Bears most wanted.
Maxwell beat Leus Du Plooy's charge to end his impressive spell but Madsen was finding the gaps and after surviving a hard caught-and-bowled chance to Mousley on 47, pulled the spinner for his ninth four to reach yet another 50 off 40 balls.
It was an impressive display of timing and placement on a slow pitch and when Wood opened his shoulders to club Brookes for two fours and a six in a penultimate over which cost 27, the momentum had swung to the Falcons.
Wood pulled Miles to deep midwicket to end a stand of 79 off 41 balls but he had helped take the Falcons to a competitive score.
Moeen launched the chase by lofting Chappell over long on which resulted in the ball being changed but when Alex Davies tried to emulate his skipper he skied a catch to mid off.
It is difficult to keep Madsen out of the game at the moment and the 39-year-old plunged forward at cover in the fourth over to hold a fine catch when Moeen checked a drive at Zaman, although he appeared to hurt his right knee in the process.
Maxwell dispatched George Scrimshaw's first two balls to the ropes but the fast bowler responded by bowling Sam Hain when he backed away to drive.
The Bears were in deep trouble when Chris Benjamin gloved a pull at Chappell through to the wicketkeeper with everything now resting for the visitors on Maxwell.
But he drilled Mattie McKiernan to long off in the 10th over and despite Mousley and Barnard's rally, the Falcons kept their discipline to record back-to-back wins.
