Honda driver Jenson Button said the team would need "every second" of testing time after a poor showing at the Australian Grand Prix.
Button had a day to forget in Melbourne
Starting from 14th, Button was well off the pace and ended up finishing 15th.
"It wasn't a very good day," said the Englishman, who said he had struggled with poor grip from his front tyres.
"We've got a test before the next race and we're going to need every second of it. Hopefully it was all rubbish today and will be all right in Malaysia."
Before the season began Button had voiced concerns about the performance of his car, and he said it soon became apparent to him that he was not going to be a contender in the opening race.
"There was massive understeer. I pitted early because the car was so bad," he said.
He said the race had suggested a major problem with the front wing, which was "not working".
I was too optimistic - Alex [Wurz] is a fair racer and a good man, and I was just sorry to screw up his race
He said he had asked the team to adjust the wing to apply more front downforce at his first pit stop but a radio problem meant they did not hear him.
"When I pitted again," he said, "we had to put a lot of wing on but it didn't make any difference."
He said the evidence suggested the wing was "stalling" - an aerodynamic phenomenon when the airflow over the wing is disturbed because the wing is wrongly designed.
It was, he said, a problem Honda suffered last season as well.
But he added: "If that proves to be the case, then it is something we can certainly address straight away."
A drive-through penalty for speeding in the pit lane dropped him even further behind.
"Once we know where our problems lie and what we need to do to fix them, we have three weeks and a test in between to start addressing them."
Apart from Lewis Hamilton's success, it was a grim day all round for the British drivers, with David Coulthard crashing out in embarrassing circumstances on lap 49.
He tried to overtake Alexander Wurz on the inside of a corner, but ended up flying across the top of the Austrian's car and into the gravel, with one of his front wheels hanging off.
"I'm a bit embarrassed," said the 36-year-old.
"I was too optimistic and I am sorry to Alex and to my guys, but this is racing.
"Alex is a fair racer and a good man, and I was just sorry to screw up his race. I went for the pass but it was over-optimistic on my part."
And Super Aguri's Anthony Davidson, heading into his first full season, was taken to hospital for precautionary checks after suffering back pain following his drive to 16th place.
The pain started in his upper back after the Englishman collided with the Spyker of Adrian Sutil on the first lap.