Coventry City were beaten 2-1 by Bury at Gigg Lane as former Sky Blue Leon Clarke scored twice.
Reda Johnson hammered in his second of the season to make it 2-1 and despite a late period of dominance, they couldn't get the crucial equaliser.
Boss Tony Mowbray named an unchanged line-up from last week's win over Chesterfield and the side starting a similar attacking vein when Jacob Murphy went close after three minutes.
He met Adam Armstrong's left sided cross in the area but his shot, which was going in, was well blocked by Peter Clarke from five-yards.
City had the better of the ball but found themselves behind in the 19th minute, when two former City players combined.
Chris Hussey put in a low free-kick which found Clarke unmarked and he hit an unstoppable finish into the top left corner.
The Sky Blues continued to have more of the ball and Adam Armstrong had a good chance just after the half-hour mark, when he was released by Jim O'Brien but he hit an early effort from outside the area inches wide of the right post.
Nathan Cameron then hit the bar with a thunderous header from a Hussey corner, before Ryan Kent was released on goal but was hauled down by Cameron. The referee didn't show a card and from the resulting free-kick, Armstrong hit a low effort narrowly wide of the right-hand upright.
That was the last action of the first-half and just five minutes after the interval, the home side had a penalty, when Clarke and Johnson tangled in the area and the linesman flagged to alert the referee's attention to give the spot-kick.
Clarke stepped up and hit it in the bottom right corner, Lee Burge got a hand to it but the penalty was too powerful and the Shakers and Clarke had their second.
Mowbray then shuffled the pack with a pair of attacking changes, as Marcus Tudgay and Marc-Antoine Fortune came on for Murphy and O'Brien.
Two minutes after the hour, City were back in it when Armstrong's corner was cleared up into the air and Johnson slammed in a header.
Tudgay then had a massive chance ten minutes later, when Romain Vincelot flicked a ball into the area and it bounced to the substitute who got a touch, but Rob Lainton was alert to divert his effort from five-yards inches wide.
With five minutes to go, the crossbar was then rattled by Sam Ricketts, who cut inside onto his left-foot from 20-yards and hit a beautiful effort which hit the frame of the goal.
Despite dominating the closing periods, City just couldn't get that crucial goal and were defeated by the Shakers.
Attendance: 4526 (1041 Sky Blues)
Referee: N Miller
Yellow cards: Johnson
Coventry City: Burge (GK), Ricketts (C), Martin, Johnson, Stokes, Vincelot, Fleck, O'Brien (Fortune 60), Kent, Murphy (Tudgay 60), Armstrong.
Subs: Charles-Cook (GK), C. Thomas, G. Thomas, Phillips, Morris.
Bury: Lainton (GK), Riley, Hussey, P. Clarke, Cameron, Mellis (Rose 69), Jones, Soares, Pugh (Brown 74), Mayor, L. Clarke.
Subs: Ruddy (GK), Hope, Dudley, Mohammed, Foulds.