Peterborough United and Leyton Orient have played out a 1-1 draw in the first leg of their League One playoff semi-final.

The hosts took the lead on 16 minutes when Britt Assombalonga, who appeared to be in an offside position, glanced his header past Jamie Jones from close range.

Orient pushed for an equaliser, and they very nearly found a way through when the ball fell to Romain Vincelot 25 yards from goal, with the defender's strike flying narrowly wide of the target.

Dean Cox also came close to levelling for the O's on the brink of half time, but he was unable to beat Robert Olejnik when played through by Kevin Lisbie.

Peterborough had the opportunity to extend their lead through Assombalonga who initially failed to control the ball inside the area, but he got a shot away at goal which was easily kept out by Jones.

Orient levelled the contest through Moses Odubajo, who rolled the ball into an empty net from close range after Olejnik palmed Dave Mooney's initial shot into the midfielder's path.

The visiting side went in search of a second goal, yet Olejnik kept Cox out on two occasions late on to ensure that the tie remains delicately poised heading into the second leg.