Jenson Button ensured that a familiar name appeared at the head of the day one timesheets at the Chinese Grand Prix, slipping in the fastest lap of second free practice as the diffuser teams returned to the fore.

Having had to play second fiddle to resurgent world champion Lewis Hamilton in the morning session at Shanghai International Circuit, Button posted a 1min 35.679secs effort the headed a Brawn GP 1-3 and sandwiched regular practice pacesetter Nico Rosberg, as the German and Rubens Barrichello proved to be the only other drivers capable of dropping into the 1min 35s. Rosberg came close to repeating his feats from Melbourne and Malaysia too, coming up just 0.026secs shy of toppling Button and claiming another P1 for Williams.

On this occasion, Toyota proved unable to run with the two other diffuser teams, and were denied a spot in the top five overall as the two Red Bull-Renaults of Mark Webber and Sebastian Vettel again proved to be the best of those teams now having to consider revising their cars for future races. Webber was just a tenth from breaking the 1min 36secs barrier, while Vettel lapped only fractionally slower. Jarno Trulli and Timo Glock took sixth and eighth for Toyota, sandwiching the second Williams of Kazuki Nakajima, which vaulted up the order after running only 19th in FP1.

Hamilton, meanwhile, dropped back to 13th fastest, despite improving his time - as everyone did in the second session - and trailed McLaren team-mate Heikki Kovalainen, who only got his hands on the team's latest front wing design in FP2. The Finn did not apparently get to run the revised 'halfway house' rear diffuser that Hamilton trialled during the day, but still ended up four places and three tenths ahead of the world champion.

Toro Rosso's Sebastien Bourdais again rounded out the top ten, with Adrian Sutil and Felipe Massa filling the gap back to Hamilton. Massa may not take much comfort from twelfth spot, but will no doubt feel happier about being closer to his 2008 title rival. The Brazilian, running without KERS this weekend, was a full 1.1secs off Button's pace, while team-mate Kimi Raikkonen was a further couple of tenths adrift in 14th.

Neither Renault or BMW Sauber enjoyed a good day on paper, with Nelson Piquet Jr and Fernando Alonso book-ending Robert Kubica and Nick Heidfeld in 17th and 18th respectively, while Force India's Giancarlo Fisichella brought up the rear after spending much of the session, like team-mate Adrian Sutil, apparently running or spinning off track. Raikkonen and Alonso were also notable casualties, although none of the day's offs led to time spent in the garage.