Hamilton and Button positive after practice
Formula 1 world champion Jenson Button said his McLaren team still have work to do in order to match the pace of the Red Bulls at the Chinese Grand Prix.
Button was third quickest after two practice sessions in China, while team-mate Lewis Hamilton was fastest.
Red Bull's Sebastian Vettel and Mark Webber were fifth and sixth but Button believes they remain the benchmark.
"You wouldn't say we're quite on their pace but we've still got tonight to work on the car," said Button.
Hamilton's fastest lap of one minute 35.217 seconds was 0.574secs faster than fifth-placed Vettel - but Button said he believed Red Bull .
"The Red Bulls are still looking pretty quick," said Button.
It's great to have a car underneath me that I can push in certain corners round here - it's reminiscent of 2008 and hopefully it'll enable us to be competitive
"They haven't shown their hand as they don't on Friday but they're quick and you can tell from their long runs that they're competitive."
Red Bull have emerged as this season's pace-setters - Sebastian Vettel won the last race in Malaysia and was leading when he hit problems at the previous two events in Bahrain and Australia. He and team-mate Mark Webber have between them taken pole position for all three grands prix in 2010.
Despite being wary of the threat posed by Red Bull, both McLaren drivers were pleased with their practice runs on Friday.
"I'm happy with the direction we've taken," said Button, who finished third in China in 2009 while driving for Brawn GP, the former guise of the current Mercedes team.
"There are a few more things we need to do but we're almost getting the maximum out of the car, especially on the long runs so it's moving in the right direction but there are a few things we need to discuss.
"My low fuel run on the soft tyre was a little bit frustrating because of traffic - there seem to be about 10 Virgin cars - which is pretty annoying but the work has been good. We've come here with a pretty good car from lap one."
Hamilton was in similarly buoyant mood after a practice session where his main rival came in the shape of Mercedes's Nico Rosberg, who set the second fastest lap of the day.
"The car is running nice and smoothly, the engine is pulling great and the balance is good as always," said Hamilton, the 2008 world champion.
"Every track I go to it always feels fantastic compared to the last time as the car is night and day better than last year.
"It's great to have a car underneath me that I can push in certain corners round here - it's reminiscent of 2008 and hopefully it'll enable us to be competitive.
"The second session was even better. We made some changes to the car and the long runs seemed very positive. We don't know what everyone is doing and I'm sure tomorrow will be a very competitive qualifying session."