Sam Ricketts will look at himself and Shrewsbury players for answers

Ten-man Shrewsbury fell apart in the final 20 minutes to concede three times in the damaging reverse, a fourth defeat on the spin, which leaves them 22nd in League One.

Josh Vela's straight red card on the stroke of half-time proved costly. Ricketts' visitors were in the game to that point and for 15 or 20 minutes after the break, until the supreme Siriki Dembele netted the second of his hat-trick on 69 minutes.

But shoddy defending full of individual errors gift-wrapped Posh most, if not all of their five goals and Ricketts says the mistakes were inexcusable.

The boss said: "I can't keep coming out and saying how well we are playing and not scoring, or we're in the game.

"For all of the good, you can't legislate for errors costing you goals. You can't keep giving opposition cheap goals like we are and expect to win games.

"In both boxes we're not commanding enough. There were a couple we should have scored beforehand.

"Then the ball goes down our end, one attack and go 1-0 down. It's not the way to win matches."

Ricketts, whose Town team face a crunch home game against fellow drop zone strugglers Burton on Tuesday, added: "I never feel let down by efforts. Individual errors can happen to anyone but the amount of errors is a cause for concern at the minute.

"We have to look at our individual performances, not just the players but myself (as well) and see why we're in a run of results like we are when clearly we shouldn't be.

"We have to analyse that and get ready for Tuesday night."

Jonson Clarke-Harris fired the opener from the penalty spot before Josh Daniels headed Shrews an instant and deserved equaliser two minutes later.

But Dembele was allowed to glide into the Salop box for a second three minutes before the break before Vela lunged in recklessly and two-footed on Dembele, for which he was given his marching orders in first-half stoppage time.

Ricketts revealed he had not seen the incident back and will take his time before reviewing it.

Town, one man down, battled well at the beginning of the second period but Dembele made it three and then four for Posh in the final 20 minutes before Jack Taylor thumped in a fifth on a miserable afternoon that leaves Salop searching for answers.

Ricketts added: "I've not seen the challenge back. So I haven't seen the severity of it, whether it was or wasn't a red card.

"If it was then there's another error that leads into the second half."

On whether he spoke to Vela about the incident, Ricketts said: "No, not yet. I'll make my own views up when I see it back. If it is then you just can't do that. It's as bad as any mistakes that lead to goals.

"In fact it's worse because it meant the team had to play for 10 men for half a game, a game there for the taking except for individual errors."

The boss said of his side's hapless errors: "Ultimately individual errors have cost us the game.

"You can't hide behind anything else. We were well in the game early on. Had the majority of play in their half. Should've scored two which were cleared off the line.

"A ball from nothing and we end up 1-0 down. It's completely against the run of play but you can't do that. I could go through every goal, it was the same scenario.

"We could've been deflated but the players weren't. We get back in the game and were well deserved of 1-1.

"And again a simple goal against, another error."