Jenson Button posted the fasted time in the opening 90-minute practice session for Sunday's Spanish Grand Prix, boosting his hopes for four wins out of the first five grands prix of the season. Button clocked 1min 21.799sec, more than a third of a second ahead of his closest challenger, Toyota's Jarno Trulli. BMW Sauber took the next two spots with Robert Kubica in third and Nick Heidfeld in fourth.
The world champion, McLaren's Lewis Hamilton, was back in 14th, 1.278sec behind Button. In between were the Williams pair of Kazuki Nakajima and Nico Rosberg in fifth and sixth, Renault's Nelson Piquet seventh and the second Toyota of Timo Glock in eighth. Felipe Massa and Kimi Raikkonen posted a disappointing ninth and 11th, with Button's Brawn colleague Ruben Barrichello in between.
Most of the teams, with the notable exception of McLaren, will have introduced upgrades to their cars at this stage of the season as they attempt to make up lost ground or consolidate early gains.