JACK Taylor’s second-half strike proved the difference as Oxford United suffered an FA Cup first-round exit for only the second time in nine seasons.

The hosts had fallen behind to Siriki Dembele’s disputed strike midway through the first half.

Josh Ruffels deservedly got them back into the game just before the break, but it was not the springboard for the U’s to go on and win the tie.

Taylor’s low shot just after the hour mark got the visitors ahead again and despite a strong late push, the U’s could not force extra time.

Both managers hinted there would be changes and the teamsheet showed five for the U’s and six for the visitors.

The hosts were planning to make six alterations, but John Mousinho’s wife gave birth on Friday, ruling the club captain out.

Posh’s rejigged line-up looked the more coherent in the opening stages, with Mo Eisa firing just wide from the edge of the box in their bright opening.

Elliott Moore had scored twice in midweek and the centre back had United’s first effort of the afternoon, heading Anthony Forde’s free-kick over.

Rob Hall fired wide from a narrow angle on the rebound after Christy Pym had parried Mark Sykes’s shot from range as United warmed to their task.

The hosts’ main threat came from Mide Shodipo, who gave Nathan Thompson a torrid afternoon.

The QPR loanee then had a penalty claim turned down after he nutmegged Frazer Blake-Tracy – and the hosts were still complaining about that when they fell behind.

Posh countered and Ruffels’ loose touch played in Dembele to beat an exposed Jack Stevens. United head coach Karl Robinson was booked for his protests, as United argued the Posh front man was offside.

It was a blow, but the home side went on to dominate the rest of the half.

Matty Taylor, captain for the day, volleyed over left-footed from Liam Kelly’s free-kick, while a spell of pressure saw Ruffels have a shot deflected over and Pym save another header from Moore.

Peterborough, who lost Thompson – presumably from dizziness after chasing Shodipo’s shadow – were getting pinned back and finally United got their reward in first-half stoppage time.

Forde’s free-kick was met by Sam Long and the ball fell perfectly for Ruffels to stab in from close range.

United should have scored again before the break when Marcus McGuane got into the box, but instead of cutting the ball back to give Taylor a simple tap-in he went for power and the ball went wide.

The break allowed Peterborough to reorganise and they were the side which looked more dangerous when play restarted.

Stevens tipped a powerful drive from Jack Taylor wide, while the goalkeeper needed to race out of his box to cut out a through ball for Dembele.

He was though beaten just after the hour mark by Jack Taylor’s low shot, after McGuane had lost the ball on the edge of United’s box.

Unlike in the first half, United were unable to find another gear after falling behind.

Sam Winnall and Joel Cooper came on from the bench, but Posh did not look troubled until the hosts’ final push.

Shodipo, who had been quieter since the break with Peterborough doubling up on him, must have thought he had equalised with a fierce strike, but Pym made an outstanding save.

It was enough to avoid extra time and see Posh into the second-round draw.

Oxford Utd (4-3-3): Stevens, Forde, Moore, Long, Ruffels, Kelly, Sykes, McGuane (Asonganyi 86), Hall (Cooper 73), Taylor (Winnall 65), Shodipo.

Unused subs: Eastwood, Jones, Elechi, Osei.

Booked: Long, Shodipo.

Peterborough Utd (3-5-2): Pym, Thompson (Edwards 43), Kent, Mason, Broom, Taylor, Reed (Brown 87), Hamilton (Clarke-Harris 74), Blake-Tracy, Dembele, Eisa.

Unused subs: Gyollai, Szmodics, Burrows, Kanu.

Booked: Hamilton.

Referee: Benjamin Speedie (Liverpool).