Chris Froome tightened his grip on the Tour de France yesterday, extending his overall lead to well over three minutes at the halfway mark with a brilliant performance in the time trial.

Tony Martin, the German world time trial champion who suffered a concussion and bruises in a mass crash on the race's first stage, blasted round the flat 33-km course in 36 minutes 29 seconds to take the 11th stage.

"When the doctor said I was okay to race [after the first stage], I targeted this stage," said Martin.

Froome, in the race leader's yellow jersey, was the last man down the start ramp and was two seconds quicker than Martin at the 22-km check point, but the Team Sky rider could not maintain the pace pedalling into a headwind over the latter part of the stage and finished 12 seconds down on Martin, with Belgian Thomas De Gendt third.

Froome was the big winner of the day, though, gaining two minutes on his nearest rival in the race standings and now leads Spain's Alejandro Valverde by 3:25.

The result will perhaps implant a nagging doubt into the minds of his rivals that there is no use in contesting for the lead anymore; better in the mountains, better in the time trials, Froome will win the Tour.

"I'm happy with how the stage went. A time trial is always a nervous day for GC [general classification] riders, so I'm happy I have extended my lead," Froome said.

Bauke Mollema, of the Netherlands, remains third overall 3:37 back with twice Tour champion Alberto Contador, of Spain, fourth at 3:54 after riding a decent, yet unim- pressive, time trial.

There was little to smile about for Mark Cavendish as the Isle of Man racer had urine thrown at him on his way to the Mont Saint Michel, yet another jaw-dropping backdrop for the 100th edition of the Tour.

"Mark is one of the big characters in the sport, some people love him, others hate him, but to do this is very sad," said Froome. "It ruins the whole atmosphere. It leaves a bad taste in your mouth. A bad taste in Mark's mouth."