Summer signing Colby Bishop made it five goals in five games as Portsmouth came from behind to beat Cambridge 4-1 and extend their unbeaten start to the season.

Cambridge took the lead 15 minutes before half-time when Joe Ironside turned in Liam O’Neil’s corner at the near post.

It took until the 45th minute for Pompey to register a shot on target when Bishop was denied by a smart stop from Dimitar Mitov.

But moments later Bishop equalised, tapping in from close range after captain Sean Raggett had nodded Owen Dale’s cross back across the face of goal.

The hosts took the lead on the hour mark when Cambridge goalkeeper Mitov dropped Tom Lowery’s free-kick and Ronan Curtis bundled the ball over the line from close range.

Mitov was at fault again as Pompey doubled their lead with 20 minutes remaining, allowing substitute Michael Jacobs’s shot from 12 yards to squirm through his legs into the net.

Defender Connor Ogilvie nodded in Reeco Hackett’s cross 13 minutes from time to complete the rout.