Craig Mackail-Smith increased his chances of starting the season with an hour of play as Peterborough were beaten 2-0 by Sunderland at London Road.
Mackail-Smith has been struggling since the end of last season with a groin injury but managed 60 minutes and could now face Derby on Saturday.
Darren Ferguson's side started well and Lee Frecklington headed straight at Marton Fulop from Daniel Blanchett's cross.
Mackail-Smith had the ball in the net after the break but was offside before Steve Bruce's side took the lead with seven minutes remaining when Andy Reid's low cross was diverted into his own net by Blanchett from close range.
Sam Gaughran then tripped Frazier Campbell and the youngster slotted home the penalty to wrap up the scoring.