Lewis Hamilton showed McLaren is again the team to beat in this weekend's Malaysian Grand Prix by setting the fastest time in both practice sessions today.
Hamilton, who took pole position in last week's Formula One season-opening race in Australia, established himself as favorite to repeat the feat here on Saturday by setting a time that was a third of a second quicker than Mercedes' Michael Schumacher and McLaren teammate Jenson Button in afternoon practice.
"It's been a good day for me," Hamilton said. "We've made a few changes to the balance of the car since the last race and I'm much happier.
"Around here, overtaking will be a little more possible than in Melbourne. Nevertheless, starting from the front will still be the best position for the race, and that's what I'll be going for tomorrow."
His time in morning practice was a 10th of a second better than that in the afternoon, with all teams electing to preserve sets of tires for Saturday and Sunday rather than use them up finding more practice pace. Tire degradation is a major issue at tropical Sepang, and fresh tires will be critical in the race.
Mercedes' Nico Rosberg was fourth fastest in the afternoon, ahead of Toro Rosso's Daniel Ricciardo and Ferrari's Fernando Alonso, although the best times were more than three seconds off last year's pole position lap, indicating much room for improvement on Saturday.
Red Bull's Mark Webber was seventh on the timesheets, with world champion teammate Sebastian Vettel down in 10th as he struggled with the balance of the car.
Toro Rosso's Jean-Eric Vergne was eighth fastest and Lotus' Romain Grosjean ninth. Ferrari's under-pressure driver Felipe Massa, who is using a new chassis here after his struggles in Melbourne, made no improvement and finished a lowly 16th.
Hamilton's day was not perfect, twice running wide in the afternoon session while practicing long-run race simulation rather than qualifying-style laps. Having been unable to match pace with Button in the race last weekend, Hamilton acknowledged he — and all other drivers — must be extra vigilant not to damage tires on Sunday.
"Looking after your tires is going to be a really tough call, trying to stop the sliding and driving with understeer if you can while keeping the lap times up," Hamilton said.
Button is regarded as one of the best in the business at nursing his tires through a race, but even he acknowledged it will very difficult to manage degradation on Sunday.
"Its tough on both tires around here with the humidity and the heat," Button said. "Unless the circuit improves a great deal, there is going to be quite a few (pit) stops out there."
Friday's times indicated a shootout between the McLarens and Mercedes in Saturday's qualifying, but Button anticipated other threats.
"Its going to be unbelievably competitive," Button said. "The Lotuses will be quick, and the Red Bulls will be quick."
Schumacher, still chasing his first podium finish since his 2010 comeback, appears better placed than ever to end that drought, as the long straights of Sepang should suit the Mercedes' innovative wing design which boosts straight-line speed.
"We had a good day on track today, and I am very happy about the work that has been done since Australia," Schumacher said. "This has enabled us to achieve reasonably consistent long runs which is obviously important in these conditions."
Friday's practice was free of major incident. Button's car had an oil leak that curtailed his morning practice while Sauber's Kamui Kobayashi had a gearbox problem that required major work but was able to emerge for the final minutes of afternoon practice.
Vettel, who snatched a somewhat flattering second place in Melbourne, was not pleased with the Red Bull's handling at Sepang.
"The tires drop off quite quickly here, which is the same for all the drivers, but we are sliding quite a bit and I would like the car to be a bit more stable," Vettel said. "We made a good step today, the potential is there, but we need to get to it."
The top four cars in Friday's times were Mercedes-powered, but it will likely be tires rather than engines that will decide Saturday's qualifying and Sunday's race.
"Our first impression is that a three-stop strategy seems likely and so far there is a difference of around 0.5 seconds between the two compounds, but the track will still evolve considerably before the race," Pirelli motorsport director Paul Hembery said.
The other potentially decisive factor is the ever-present risk of tropical downpours in Malaysia. The showers held off on Friday but it is very rare for a race weekend at Sepang to avoid rain altogether.