DC shines as Webber shunts.

Red Bull Racing endured a day of two halves during the opening couple of practice sessions for this weekend's Turkish Grand Prix, with David Coulthard showing strongly towards the upper reaches of the timesheets, but Mark Webber going off heavily in the sister RB4.

Coulthard was a lowly 17th-quickest in the morning session, one spot behind Webber, but vaulted up the order in the afternoon to end day one fifth-fastest overall, just four tenths of a second shy of the ultimate pace. The experienced Scot has only finished in the points once in Istanbul - in seventh place back in 2005, the race's inaugural edition - but he is hoping to open his account for 2008 on Sunday.

"That was similar to the Friday session in Spain," the 37-year-old reflected afterwards. "There were no major problems; it was all about following the track evolution and making sure we had the balance right.

"There are a lot of long corners on this circuit - you can see people are going off quite easily - so it's critical to get the front end right here. We'll look at the data now and decide what we'll do for Saturday."

One of those people who went off 'quite easily' - and without doubt the most spectacularly - was Webber, who shunted heavily in the afternoon, bringing out the red flags. The Aussie - who has scored points in each of the last three races - accepted full blame for the accident, but knows he is facing an uphill struggle to atone for his misdemeanour from hereon in.

"Going off the track at turn six was 100 per cent my fault," the 31-year-old candidly acknowledged. "I didn't respect the green Astroturf that sits on the outside of the track enough.

"I was a bit too loaded up on the outside of the track, the Astroturf was a bit damp and I went off. It was my fault. I apologise to the guys and we'll bounce back from this on Saturday."