Leyton Orient slipped to four points off the League Two play-offs after suffering a 4-2 defeat to league leaders Cambridge United.

A brace from Joe Ironside and goals from Paul Mullin and Shilow Tracey bolstered the U's automatic promotion hopes while denting the O's with the latter having just three games left this season.

O’s manager Jobi McAnuff made one change to the starting line-up that sealed a 2-0 win over Barrow AFC with Ouss Cisse coming in to replace Craig Clay as well as taking the armband as Ruel Sotiriou returned from injury to be named on the bench.

In the fifth minute Orient forward Danny Johnson raced in behind to collect a long ball forward from Lawrence Vigouroux and forced Callum Burton into an acrobatic save which won the hosts a corner.

The set-piece amounted to nothing and the U’s broke on the counter attack with top goal scorer Paul Mullin the one with the shot at the end of the run but it was comfortably held by Vigouroux.

Left winger Louis Dennis then flashed an effort wide of the left post after some good passing plays around the box from Orient between the likes of Dan Kemp, Conor Wilkinson and Tunji Akinola.

In the 14th minute Johnson controlled a bouncing ball and looked for the bottom corner with his right foot but Burton made the save. It went out for a corner which was whipped in by Kemp and led to a second but that time it made no impact.

Five minutes later the visitors opened the scoring as Joe Ironside turned in a cross from left-back Jack Iredale from close range.

Both sides attacked but never really threatened after the first minute of stoppage time when Dan Kemp fired home a rebound after the U’s failed to clear a Dennis cross to make it 1-1 heading into the break.

Cambridge United restored their lead in the 64th minute as Shilow Tracey headed home his first goal since joining the club on loan from a rebound following a corner.

Things went from bad to worse for the O’s as Jamie Turley fouled Craig Taylor inside the box to award the U’s a penalty and up stepped Mullin who made no mistake to stretch their lead to 3-1 just five minutes later.

Orient didn’t give up as they pulled one back in the 73rd minute as Wilkinson's header rebounded off the post and goes in off Cambridge defender Declan Drysdale.

It was however short lived as the U’s made it 4-2 in the 80th minute as Ironside grabbed his second of the match by firing the ball into the roof of the net with his right-foot.

In the 94th minute O's forward Conor Wilkinson was clipped and brought down inside the box but the referee waved it away much to the disgust of the hosts.

Leyton Orient: Vigouroux, Akinola, Turley, Happe, Brophy, Cisse (McAnuff 81), Kyprianou (Clay 62), Dennis (Sotiriou 81), Wilkinson, Johnson.

Unused subs: Sargeant, Widdowson, Coulson, Sotiriou.

Cambridge United: Burton, Knoyle, Drysdale, Taylor, Iredale, Hannant, Digby, Boateng (May 90+4), Tracey (Dunk 65), Ironside, Mullin (O'Neil 90+4).

Unused subs: McKenzie-Lyle, Okendina, Alese, Neal.