Red Bull Racing's David Coulthard crashed out in qualifying for the Monaco Grand Prix on Saturday, causing extensive damage to his Renault-powered RB4.

The accident occurred towards the end of the second qualifying session, when the Scot came out of the tunnel and was braking for the harbour chicane. As he hit the brakes, his car was pitched right into the barriers, sending him careering off down the escape road.

Although he escaped uninjured and still qualified tenth, he wasn't 100 per cent sure what caused the off.

"I was doing around 185kph when the incident happened, and I went into the wall quite hard," he explained.

"When I hit the brakes the car turned, I was going over a rise so it's possible I locked the rear axle, but normally when that happens, you can just release the brake a little bit.

"We'll check the car and see if anything was going wrong at the rear, as it turned very quickly. It's normal for the rear to go light when you brake there, as we don't have engine braking or anything like that, but you drive with that in mind, so I'm surprised what happened was so violent.

"But, we'll get the car back, look at the data and then we'll know."

Red Bull Racing team boss Christian Horner was relieved that the Scot was uninjured after such a high-speed accident.

"The main thing after such a nasty looking incident is that David is completely unharmed," said Horner.

"The car's damage is relatively contained so, after a difficult weekend for him, which has included engine throttle problems on Thursday, a gearbox oil pressure issue this morning, and a large accident in Q2, to still be tenth on the grid is positive. I'm sure David will be fine in tomorrow's race."

Mark Webber, meanwhile, qualified one spot ahead in the sister car and the Aussie reckons he now can break into the top eight in the race and notch up some more points.

"We had a clear run with no problems," he added. "I was locking up quite a lot, but there was no particular sector of the lap that was worse than the others - we'll just have to see how things go tomorrow.

"Seventy-eight laps is a long race and there's some uncertainly over the weather, so hopefully we can get some points."