Jenson Button believes his McLaren team will face stiffer competition in Malaysia this weekend than during his dominant Australian win last Sunday.
The Englishman said he felt Red Bull, Mercedes and Lotus had all under-performed in Melbourne.
"We'll be competitive, but you'll see other teams up there as well," he said.
"We got it all together at the weekend apart from a couple of things. When Red Bull get their act together - and a few others - they'll be very competitive."
Button said his comfortable win in the season-opening race had "given massive confidence in the team that we can really fight for this [championship]".
It is a marked contrast to last year, when Red Bull and Sebastian Vettel dominated the opening races on their way to a comfortable title victory.
Button said he expected McLaren's car to be competitive in Malaysia because the circuit has a similar mix of high- and low-speed corners to Spain's Circuit de Catalunya, where the team went well in pre-season testing.
He said there was "no reason" why McLaren could not finish one-two at Sepang on Sunday.
"It's about keeping it all together and not making mistakes," he said. "The team has done a great job since the start of the year."
Button's team-mate Lewis Hamilton dropped from pole position to finish third behind Vettel in Melbourne, and he looked dejected after the race.
"The race didn't go as I wanted to," Hamilton said, "and I think it's fair to be disappointed. I don't think I should disguise that."
He revealed that a clutch problem had affected his start and that he had suffered with a set-up problem during the race.
"I had a bit too much oversteer in the high speed," he said. "I had a different front wing set-up than Jenson and it wasn't the right one."
Vettel admitted that Red Bull had not been strong enough to challenge McLaren in qualifying even though he and team-mate Mark Webber produced perfect laps.
"We were not quick enough to put the car on the front row. We had better race pace, but the win was too far so there is a lot for us to do," he said.
"We got everything out of ourselves in that race. All round they had a stronger package. In the end we did our best, we had a very good race, but in qualifying we were lacking.
"They had the upper hand and they will have the upper hand already this weekend, but this is a different track with different characteristics and we'll see what we can do."