ISTANBUL McLaren's Jenson Button set the pace in Turkish Grand Prix practice on Friday while Formula One world champion Sebastian Vettel crashed in the morning and missed the entire second session.
Vettel, the championship leader after winning two of the first three races, gave his Red Bull mechanics plenty of extra work after spinning into the barriers at the rain-soaked Istanbul Park circuit.
The 23-year-old German, who has been on pole position for the past four races, spun at the exit of the challenging triple apex turn eight.
The session was red flagged with 27 minutes remaining, with marshals clearing mud off the track while the battered Red Bull was hoisted onto a flatbed truck and brought back to the pitlane.
"There was some water on the exit. There was nothing I could do," he said over the team radio after his car skidded down the barriers to a halt.
The damage was extensive and Vettel was a mere spectator in the afternoon when the sun made a weak appearance and temperatures rose notably. He will now go into the weekend with no dry weather mileage under his belt.
Button, winner in Turkey with Brawn in his 2009 championship year, was fastest in one minute 26.456 seconds at the front of a quartet of Mercedes-powered cars.
Mercedes' Nico Rosberg was second on the timing screens, ahead of McLaren's 2010 race winner Lewis Hamilton and Michael Schumacher.
Red Bull's Australian Mark Webber, on pole in Istanbul last year, was fifth.
Ferrari's Fernando Alonso was fastest in the morning in a largely meaningless session full of spins and spray with a best lap of 1:38.670, ahead of Rosberg and Schumacher in a strong showing by the Mercedes team.
Alonso spun in the afternoon, his Ferrari crawling back to the pits with a hydraulics problem as marshals gave him a helping push.
Ferrari's Brazilian Felipe Massa, a three times winner in Turkey, was seventh and sixth after complaining of brake problems.
McLaren had propped up the rear in the morning, with Hamilton 24th and failing to set a timed lap while Button did just four as the team focused on practice starts.
A little piece of history was made at the slower end of the pitlane in the first session, with India having two Formula One drivers on track together for the first time at a grand prix weekend.
Karun Chandhok, the Team Lotus reserve, was given time in the car instead of Finland's Heikki Kovalainen while HRT's regular racer Narain Karthikeyan was also out on track.
Chandhok, who made his race debut with HRT last year before Karthikeyan made his comeback this season, had taken part only briefly in the first practice in Australia in March when he was first out of the pitlane and promptly crashed.
Karthikeyan did not take part in that practice session due to problems with his car.
(Editing by Patrick Johnston and Ken Ferris; To query or comment on this story email email@example.com)