Joe Ledley's second-half header gave Celtic a deserved point against Rennes at the Route de Lorient but Neil Lennon was left to count the cost of a defensive mistake.

Around the half-hour a long punt by the home goalkeeper, Benoît Costil, was making its way harmlessly through to Fraser Forster in Celtic's goal but Cha Du-ri helped it on then watched in horror as the ball slipped past his goalkeeper and into the net. The South Korean was playing in midfield and back as the last man only because Glenn Loovens and Charlie Mulgrew were still at the other end following the set piece.

It looked as if another disappointing European night was on the cards for the Scottish side but in the 70th minute Ledley flicked a Mulgrew free-kick over Costil to give the visitors a draw, although they remain bottom of Group I on goal difference.

The Celtic manager, Lennon, said he was satisfied with a point. "It would have been a real shame having played so well to lose a game with the goal we conceded," Lennon said. "But credit to the players in the second half, we weathered a wee bit of a storm.

"Fraser Forster showed his character, tremendous saves, but we created some good chances and I felt on the balance of play we should have won the game. It's a testament to the team after the weekend. They come and show the quality. I'm very, very proud of them tonight."

Lennon praised Ledley, who played out of position at left-back. "He's a terrific player and no matter where you ask him to play he does a great job for the team," the manager said. "He's gradually got better and better and he was marvellous tonight against really top-class players. To get the goal was a bonus but his overall display was fantastic."

Celtic started confidently and Ki Sung-yueng had an early drive from long range which forced a save. Ki then went down in the box following a challenge from Vincent Pajot but his claims for a penalty went unheeded by the Polish referee, Robert Malek.

The French club worked their way into the game and in the 12th minute the captain, Kader Mangane, headed a looping free-kick from Julien Féret wide at the back post before a drive by Youssouf Hadji was headed over by Victor Wanyama for a corner, which the visitors survived.

Celtic's first real chance came in the 24th minute when the stand-in captain, Mulgrew, threaded a long pass through to Anthony Stokes, who smartly turned Mangane, but Costil diverted the Irishman's shot over the bar for a corner which came to nothing.

That near miss appeared to energise Lennon's side but they were undone when the mix-up between Du-ri and Forster handed the home side the lead.

Celtic still looked a bit shell-shocked at the start of the second half. In the 49th minute, though, Loovens did well to deny Alexander Tettey who had burst into the box to get on to a pass by Abdoulrazak Boukari, the Dutchman shepherding the ball back to Forster.

The game swung from end to end and in the 70th minute Celtic got their deserts when Ledley jumped high in a packed goalmouth to head in. Both sides went all out for the winner and in the dying seconds Forster made yet another fine block from Jonathan Pitroipa, but the visitors were worthy of a point.