Fernando Alonso and Jenson Button are pleased with the gains McLaren have made, but fear the conditions in China could negate their progress.
The Woking-based squad were bottom of the timesheets at the season-opener in Australia, but they improved by up to 1.5s in Malaysia and found themselves battling the Force Indias.
Although pleased with the steps the team have taken forward, Alonso warns the cooler conditions could affect them negatively at Shanghai this weekend.
"I don’t think our car package will be as well suited here as it was in Malaysia, especially if the weather is as cold and windy as it usually is in early springtime in Shanghai," the double World Champion said.
"Nonetheless, the steps we took between Australia and Malaysia were extremely impressive: it was a great feeling to be able to mix it with other cars and drivers, and I hope we can do more of the same in China this weekend.
"That sort of progress really gives the whole team belief and confidence in the path we’re taking, so I hope we can keep moving forwards every time we take to the track."
Button is equally impressed by the improvements, but warns the progress could be masked.
"However, China’s two long straights – each preceded by slow- to medium-speed corners – will place extra emphasis on the power-unit," he said. "And there is a feeling that the expected cooler weather will make it harder to generate tyre temperature – which could mean that any progress we make doesn’t necessarily translate to a laptime benefit.
"But there is definitely progress being made, and it’s great to be able to play a role in helping move the whole team forwards. It’ll be fascinating to see how much change we can effect over the forthcoming races."