Reds 1 (Berry 90+4)
Peterborough 1 (Washington 16)
It had looked like disappointment for the Reds after Peterborough went ahead in the first half but although it took until the last minute of added time, Luke Berry eventually found the equaliser, heading in Hourihane's corner.
Making several changes to his side, this afternoon's game provided Lee Johnson with a chance to experiment with the squad slightly as the play-offs now look out of reach.
Handing a full debut to Jack Cowgill and giving starts to other youngsters, the team sheet looked as though it was a glimpse into what could be the future for the Reds.
Despite starting brightly, it was the visitors who got the first sight of goal when Paul Digby gave away a free kick in the opening 10 minutes.
The effort was struck well but it could not clear the height in the Barnsley wall as the new-look squad looked to settle down.
It was a mistake at the back that led to Posh taking the lead just after the fifteen minute mark.
Jack Cowgill's mistimed clearance presented Conor Washington with a chance to score and he reacted quickly with the outside of his foot to beat Adam Davies.
Peterborough continued to keep the Reds busy at the back as their fast paced passing and closing down was causing problems for Lee Johnson's side.
Luke Berry had a chance to score on 33 minutes after he and Milan Lalkovic combined to caused trouble in the Peterborough area.
It was Berry who ended up with the ball at his feet around 10 yards from goal and the midfielder released a shot but it dragged wide of the far post.
Five minutes later Conor Hourihane found himself through on goal after a ball over the top from Paul Digby was misjudged by the Peterborough keeper.
Despite Alnwick looking to try and handle the ball outside of the area, play continued but Hourihane could not find the back of the empty net.
Peterborough came out for the second half strongly and after just a minute of the second period they had a corner following a block from Lewin Nyatanga.
Although nothing came from the corner, there was some trouble caused by the delivery as the Reds tried desperately to get it out.
Only a minute later the Reds had their best chance of the game when Josh Scowen pulled the ball back to Hourihane on the edge of the area and the Irishman hit the ball towards goal with the side of his foot, with the ball just missing the top of the bar.
Hourihane continued to chip away at Posh with some good deliveries. The pick of the bunch again saw the Peterborough keeper misjudge the flight of the ball and Winnall met it at the far post but headed into the side netting.
Bringing on Ben Pearson and Declan John to try and find a way back into the fixture, Lee Johnson's tactics changed for the final forty minutes as Peterborough had been by far the better side in the first half.
The changes did see some improvement in the way the Reds went forward but ultimately the power and skill of Peterborough was proving too much to handle.
Winning a corner 71 minutes after a good run from Scowen ended in a blocked effort, this provided a chance to maybe find something, but again the Reds were weak in attack.
Peterborough were reduced to 10 men with fifteen minutes left to play after Posh's Kgosi Ntlhe was the recipient of a second yellow for a foul on Berry.
This gave the Reds a slight advantage as they could now pass the ball more freely in the middle of the park.
Even with the one man advantage the Reds were left frustrated by their attacks as the Posh back line stood strong.
In stoppage time the Reds won a corner in the dying moments of the game with even Adam Davies going up for the set piece.
Having already been awarded Man of the Match, Luke Berry was the man on the end of the cross and he headed low to put the Reds back on level terms with what turned out to be all but the last touch.
Reds: Davies, Holgate, Cowgill (65), Nyantanga (C), Smith (54), Hourihane, Digby (55), Berry, Lalkovic, Winnall, Scowen.
Subs: Dibble, Bree (65), Pearson (55), John (54), Oates, Williams, Cranie.
Peterborough: Alnwick, Smith Ntlhe, Bostwick, Sheehan, Washington (90), Santos, Zakuani, Anderson, Maddison (73), Beautyman.
Subs: Henry, Brisley, Oztumer (73), Newell, Burgess, Norris, Edwards (90).
Referee: Sebastian Stockbridge
Attendance: 8924 (380 Away)