Pompey’s draw with Wycombe opened the door for Peterborough who took back top spot in League One with a 4-2 win at Gillingham.
Kenny Jackett’s men had knocked the Posh off the top with the win in the previous round of fixtures.
But things changed again with Peterborough hitting back from behind at the Priestfield Stadium.
Jamie Walker gave Steve Evans' side an interval lead before Gillingham hit back through Callum Reilly and Mark Byrne early in the second half.
Siriki Dembele equalised for the visitors after the break and then set up Ivan Toney, with Callum Cooke adding a late fourth.
Barnsley's home game against Burton was postponed after a medical emergency had delayed the kick-off at Oakwell.
Sunderland also bounced back from their first league defeat of the season last week at Burton with a convincing 4-1 home win against Rochdale.
Josh Maja and Lynden Gooch both struck doubles to put the Black Cats out of sight before Matt Done scored Dale's consolation.
John Marquis' double secured Doncaster their third straight league win, 2-1 at home against Bradford.
Marquis struck his sixth and seventh goals of the season in either half and although George Miller pulled one back, Rovers extended their unbeaten league run to six games and sent Bradford to a fifth successive defeat.
Walsall put their first league defeat of the season last week behind them with a 2-1 win at struggling Oxford.
Morgan Ferrier and Zeli Ismail scored in either half while James Henry's effort for the U's came too late as the Saddlers moved up to fifth.
Charlton secured a fourth straight league victory.
They beat winless Plymouth 2-1 at the Valley.
Karlan Ahearne-Grant cancelled out Graham Carey's early header for Plymouth and added a second late on after Lyle Taylor's first-half penalty had been saved by visiting goalkeeper Matt Macey.
Simon Cox fired the only goal as Southend beat Fleetwood 1-0 at Roots Hall.
Cox's goal early in the second half ensured a first defeat in eight league games for Joey Barton's side, who had Jamie Wallace sent off in stoppage time for his second bookable offence.
Blackpool extended their unbeaten league run to seven matches after a goalless home draw against Luton.
Lee Novak fired the only goal to clinch Scunthorpe their first home league win of the season, 1-0 against Shrewsbury, and Bristol Rovers also notched their first home success with a 3-1 win against Coventry.
Rovers raced into a three-goal lead thanks to Gavin Reilly, Tom Lockyer's header and Ollie Clarke. Dominic Hyam headed Coventry's reply on the stroke of half-time.
Accrington stretched their unbeaten league run to eight matches after holding on to beat AFC Wimbledon 2-1 at home.
Billy Kee and Sean McConville put the home side in control and although Scott Wagstaff reduced the arrears, Accrington held on.