Leyton Orient were knocked off the top of League Two despite claiming a 1-1 draw at Northampton Town after a sensational finish.

The visitors dominated the match and only an exceptional performance from home goalkeeper Adam Smith denied them maximum points after a string of superb saves in the second half.

But just as the game was heading for a draw Northampton stole the lead after an injury time header from Dominic Calvert-Lewin.

However Orient equalised with the last kick of the match as Dean Cox hit a stunning free-kick to earn a point after an astonishing climax to the game.

The O’s made two changes with Ollie Palmer handed his first league start in place of Paul McCallum. Bradley Pritchard also returned to the midfield with Lloyd James starting on the bench.

Palmer had the chance to mark the occasion with an early goal but the striker sent his header over the bar from Sean Clohessy’s cross.

Orient settled into the game better and went close after Pritchard set up Cox but his low strike was deflected out for a corner.

Northampton were struggling to make any headway in attack and their efforts were summed up by a long-range effort by Sam Hoskins which he dragged well wide.

The hosts had an opportunity through Calvert-Lewin but he headed wide of the O’s post.

Orient went close again when Cox’s cross was spectacularly hit by Jay Simpson’s overhead kick but it flew wide of the target.

Calvert-Lewin had an opportunity at the start of the second period when he took the ball around goalkeeper Alex Cisak but he took it too far wide and eventually Orient clear the danger.

Simpson had a chance on the break for Orient but a defender got back and intercepted and keeper Smith claimed the ball.

Smith was forced into a decent save to tip Palmer’s header round the post after a cross from Jack Payne.

Orient kept the pressure on and were only denied the opener when Connor Essam’s header was superbly pushed out for a corner by Smith.

The visitors created another chance when Palmer nodded the ball on but Sammy Moore could only prod the ball straight at Smith.

Ian Hendon made his first change midway through the half when Blair Turgott was brought on in place of Moore.

The O’s came so close again to taking a deserved lead through Mathieu Baudry but the captain’s shot was superbly parried by the Northampton keeper.

Simpson was the next to have a big opportunity but his low strike was blocked by the outstanding Smith.

It was continuous pressure from the O’s but once again Smith came to the rescue as he brilliantly saved Simpson’s close-range shot.

Northampton created their first chance of the game when substitute Alfie Potter broke clear but Cisak blocked the effort.

Orient made another change as they pushed for a winner with McCallum coming on for Palmer.

Payne fired in a fizzing effort from the edge of the area but the midfielder’s strike was straight at the keeper.

The hosts almost snatched a late winner through John-Joe O’Toole but his hooked effort was claimed by Cisak.

McCallum picked up a bad injury in the last ten minutes and was stretchered off with Scott Kashket replacing him.

There were six minutes of injury time and incredibly Northampton took the lead through Calvert-Lewin's header.

But with virtually the final kick off the game Cox hit a stunning free-kick into the top corner for a sensational equaliser.

Northampton Town: Smith; Furlong, Brisley, Diamond, Buchanan (O’Toole, HT); Watson, Byrom, D’Ath (Potter, 57), Hoskins (Richards, 57); Adams, Calvert-Lewin

Subs not used: Horwood, Lelan, Hackett, Clarke

Leyton Orient: Cisak; Shaw, Essam, Baudry, Clohessy; Cox, Payne, Moore (Turgott, 67), Pritchard; Palmer (McCallum, 77, Kashket, 87), Simpson

Subs not used: Dunne, James, Grainger, Moncur

Referee: Michael Bull

Attendance: 5,061 (800 away fans)