Promotion-chasing Cambridge came from two goals down to secure a deserved 4-2 victory at Oldham.
Keith Curle's first home game in charge of Oldham was a miserable one as Davis Keillor-Dunn missed a second-half penalty having earlier given the hosts their two-goal advantage.
Oldham went ahead early when Keillor-Dunn met Andrea Badan's through-ball before tucking past goalkeeper Callum Burton at the second attempt.
After 11 minutes, Keillor-Dunn struck again, converting Nicky Adams' whipped-in cross from close range.
Oldham loan keeper Laurie Walker - making his EFL debut aged 31 - saved brilliantly from Paul Mullin, before the U's halved the deficit in the 25th minute.
Mullin netted his 26th goal of the season from the spot after Raphael Diarra had tripped Greg Taylor.
Jack Iredale's deflected strike from 18 yards made it 2-2 and he pounced again seconds before the interval after meeting Mullin's smart back-heel.
Keillor-Dunn missed his hat-trick opportunity in the 69th minute when Burton saved his penalty after Kyle Knoyle had bundled over substitute Bobby Grant.
Cambridge sub Luke Hannant then curled home direct from a corner to complete the scoring.