Kimi Raikkonen put a revived McLaren back on top of the timesheets after today's practice session ahead of this weekend's British Grand Prix.
The Finn, overall runner-up last year but little more than an also-ran in the first half of this season, lapped in one minute 18.655 seconds, a mere 0.005 of a second quicker than Sauber's Gianarlo Fisichella.
Fisichella's day was bittersweet, his car finding its pace only after the engine was changed in the morning - a move that imposes a 10 place penalty on the starting grid after tomorrow's qualifying.
Ferrari's world champion Michael Schumacher, dominant winner of nine of the season's 10 races and seeking his 80th career victory on Sunday, was third fastest.
Raikkonen's team-mate David Coulthard, twice a winner at Silverstone, was fourth while compatriot and home favourite Jenson Button in a BAR was fifth.
Ferrari's Rubens Barrichello had earlier fired up his challenge for a second successive win in Britain with the fastest time in the day's first practice.
The Brazilian, without a victory so far this season, won from pole position with a lap record time in 2003 and is eager to repeat the feat after finishing runner-up six times in the last 10 races.
Williams looked strong in the first session, with Colombian Juan Pablo Montoya third and Spanish stand-in Marc Gene fourth quickest in his second successive race as a replacement for injured Ralf Schumacher.
Germany's Timo Glock crashed with eight minutes remaining in the second session when his Jordan lost a rear wheel. The test driver emerged from the car unscathed.