James Norwood grabbed his first goal for the Blues but Ivan Toney equalised for Peterborough with the scoreline 1-1 between Town and Posh at half-time at London Road.
Gwion Edwards made his first League One appearance of the season from the start against his old club with the Blues otherwise unchanged from the team which drew 1-1 with Sunderland last weekend.
Edwards, who was a starter in the much-changed line-up for the Carabao Cup defeat at Luton on Tuesday having returned from his groin injury, came in on the left of midfield for Luke Garbutt, who is out for a month with a knee problem.
Prospective new right-back Kane Vincent-Young travelled with the Town squad with his £500,000 move from Colchester agreed subject to his medical.
For Posh, who went into the match having lost all three of this season’s previous games, Marcus Maddison and Niall Mason returned to the starting line-up after missing their 1-0 Carabao Cup defeat to Oxford in midweek.
Prior to kick-off manager Paul Lambert went over to salute the loud 4,000-strong Town away following who had made the relatively short trip to Cambridgeshire.
The Blues saw most of the ball in the early stages and went in front in only the fourth minute via a calamitous mistake from Posh keeper Christy Pym.
Left-back Myles Kenlock crossed into the box from deep and Pym, who Town spoke to in the summer before signing Tomas Holy, looked set to make a routine catch. However, the former Exeter man collided with skipper Mark Beevers and the ball dropped to Norwood behind him.
The Town striker gleefully accepted the gift, calmly picking his spot and slotting into the empty net before wheeling away to celebrate in front of the home support.
As he did so, Pym claimed in vain to referee Martin Coy that he had been fouled, presumably presuming his collision had been with Norwood rather than one of his own players.
Having got their noses in front the Blues continued to press and threatened a second in the seventh minute after a quick Kayden Jackson break down the right. Eventually the ball was cleared to Flynn Downes 25 yards out but the midfielder’s shot flew over.
Rowe hit a low effort through to Pym on 11, then Maddison sent a freekick from the right across the Blues box but Ivan Toney was unable to reach it.
Posh were starting to see more of the ball - and win freekicks in dangerous areas - and on the quarter hour the ball was half-cleared to Maddison, who blazed over from just outside the box.
Two minutes later, Kenlock crossed from the left and Norwood was unable to get over it at the far post and the ball flew off his head and into the fans behind the goal.
But Peterborough were looking more of a danger and they might well have levelled in the 21st minute. Former King’s Lynn full-back Frazer Blake-Tracy beat Cole Skuse on the left, then sent over a superb ball which Toney headed too close to Holy, who claimed confidently. The ex-Newcastle youngster will have felt he should have scored.
But Toney didn’t have to wait too much longer for a goal. In the 29th minute Luke Woolfenden gave away a freekick on the Peterborough left for a rather needless foul on the Posh striker. Maddison deftly chipped the freekick into the box and Toney rose unmarked to nod his second goal of the season past Holy.
Town looked to hit straight back. Edwards cut in from the left and smashed a deflected shot which Pym did well to claw away from the corner of his net.
On 35 Edwards drew Norwood’s ire for flicking the ball away from the striker as he was about to volley a cross from the right towards goal. The ex-Posh winger indicated he hadn’t heard a call as he tried to head the ball into the box.
Four minutes later, Edwards shot over the bar, much to the delight of his old supporters, after the ball had been cleared to him in the aftermath of a rehearsed Blues freekick which hadn’t come off.
In the final scheduled minute before the break, Maddison spotted Holy out of his goal and tried an audacious effort from his own half but the Blues keeper reacted quickly to save to his right.
However, the home side were looking the more likely scorers of the game’s third goal as referee Coy ended the first period.
Town had started brightly and had controlled the game in the opening 10 minutes in which they were gifted Norwood’s opening goal.
But gradually Posh took charge and they might well have been on terms prior to Toney’s equaliser.
Aside from Edwards’s strike just after Peterborough’s goal, the Blues had shown little threat once parity had been restored and will have to improve significantly after the break if they are to claim their first win at London Road since 1972.
Peterborough: Pym, Beevers (c), Kent, Eisa, Knight, Maddison, Reed, Toney, Blake-Tracy, Boyd, Mason. Subs: O’Malley, Butler, Dembele, Tasdemir, Ward, Kanu, Burrows.
Town: Holy, Donacien, Chambers (c), Woolfenden, Kenlock, Skuse, Downes, Rowe, Edwards, Jackson, Norwood. Subs: Norris, Wilson, Judge, Roberts, Dozzell, El Mizouni, Huws. Referee: Martin Coy (Durham).