OXFORD United’s nine-game unbeaten run came to an end at basement boys Bradford City as two sloppy first-half goals proved their undoing.

The U’s remain above the Sky Bet League One relegation zone, but a frustrating afternoon saw Karl Robinson’s side suffer their first defeat since October 9.

United dominated the opening 25 minutes, but their fast-start was silenced by quickfire goals from David Ball and former Oxford loanee Jack Payne, which sparked a bumper Valley Parade crowd of more than 19,000 into life.

The visitors were still in the game, but they were unable to make their superior possession count, while they showed a defensive fragility which had not been seen during their strong run.

Nathaniel Knight-Percival was sent off late on for the home side, but United, who entered the match high in confidence, cut a frustrated outfit at the final whistle.

Marcus Browne returned to United’s forward line in the only change from Tuesday’s Emirates FA Cup victory at Forest Green Rovers.

Luke Garbutt dropped to the bench as a result, with Josh Ruffels and James Henry moving to left back and midfield respectively.

The hosts cut ticket prices to £1 in the hope the extra backing would inspire the Bantams to end their miserable 11-match winless run in all competitions.

But the noise from the home supporters was soon hushed by United’s fast start.

Measured build-up play led to a fifth minute corner and Browne’s delivery was headed wide by Curtis Nelson at the back post.

Ruffels then broke in to the area moments later and his cross deflected on to the top of goalkeeper Richard O’Donnell’s net, but Bradford cleared the resulting set-piece.

United were then presented with a golden opportunity on 11 minutes, when Browne took advantage of a Paul Caddis error and raced into the area.

The West Ham United loanee unselfishly looked for a teammate, but his pass was behind Henry and Mackie stretched for the ball, scuffing an effort which was easily cleared.

James Henry then forced a fine low save from O'Donnell as the visitors' dominance continued.

But United were to rue not taking their chances as the hosts steadily grew into the game and gave their bumper crowd something to cheer about on 26 minutes.

The Bantams won their first corner of the game and Eoin Doyle flicked on Payne's corner to Ball.

Goalkeeper Simon Eastwood got a hand to the midfielder's header, but the ball still found its way into the net. 

Suddenly the hosts had their tails up and extended their lead just two minutes later.

Once again, United were slow to react to a loose ball and, after Jamie Hanson had blocked a Doyle shot, Lewis O'Brien squared for Payne to fire home.

Oxford were on the ropes and the offside flag saved them from conceding a third on 35 minutes when Anthony O’Connor thought he had netted after the U’s had failed to deal with another Payne set-piece.

United still caused Bradford problems and Nelson had a strong penalty shout turned down at the end of the half, but referee Darren Drysdale waved away the visitors’ angry protests.

Karl Robinson’s side needed to score first after the break to have a chance of keeping the contest alive and they started brightly, with Browne firing wide and Ruffels off-target with a diving header.

However, once again, United were saved by the assistant referee, as an unmarked O’Brien headed home on 56 minutes, but the goal was disallowed for offside in the build-aup.

United had kept eight clean sheets in 11 games ahead of the fixture, but they looked shaky and nervous in defence.

Gavin Whyte and Browne were still causing Bradford problems in the wide areas, however they lacked a ruthlessness to punish the home side.

United rolled the dice with seven minutes to go and made a triple substitution, with Sam Smith, Cameron Norman and Luke Garbutt coming on.

Oxford refused to give in, while tempers boiled over on the pitch when Knight-Percival was sent off for an elbow on Smith.

Eight minutes were added on and Smith headed Garbutt’s cross wide, while Nelson hit a post.

But they were unable to set up a nervy finish as the travelling U’s fans left a noisy Valley Parade disappointed.

Bradford City (4-1-3-2): O’Donnell, Caddis, O’Connor, Knight-Percival, Chicksen, Henry, L O’Brien, Payne (J O’Brien 83), Ball, Doyle (McGowan 88), Bruenker (Miller 79).

Unused subs: Wilson, McGowan, Wood, Devine, Wright.

Booked: O’Connor.

Sent off: Knight-Percival.

Oxford Utd (4-3-3): Eastwood, Hanson, Nelson, Dickie, Ruffels (Garbutt 83), Mousinho (Norman 83), Brannagan, Henry, Browne, Whyte, Mackie (Smith 83).

Unused subs: Mitchell, Long, Raglan, James.

Booked: Brannagan, Mousinho, Whyte, Smith.

Referee: Darren Drysdale (Lincolnshire).

Attendance: 19,034.