Following another disappointing outing, McLaren boss Martin Whitmarsh has told Sergio Perez to roll his sleeves up and get stuck in.

The Mexican was the subject of much debate in the moments following yesterday's Chinese Grand Prix, Kimi Raikkonen and Lewis Hamilton - the man Perez replaced at McLaren - both discussing his antics ahead of the podium ceremony.

While Raikkonen blamed Perez for the incident which saw the Finn run into the back of the McLaren, causing damage that was to cost him around 0.25s a lap and any hope of the win, Hamilton was heard to say; "he was all over the place".

Until now, because of the obvious shortcomings of the MP4-28, Perez has been given a certain amount of leeway, however, his critics insist that his drop in form extends well into 2012 indeed, round about the time he was signed by the Woking outfit.

With the multi-champions aiming to take a major step forward in Spain, and empowered by Jenson Button's performance yesterday, Whitmarsh has warned Perez that it is time to get stuck in.

"I think he's been very polite so far this year," he told reporters in Shanghai, "I think he needs to toughen up.

"I think he's been generous in allowing people past him," he added, a comment that others, including Raikkonen might take issue with. "But he was a bit more robust today.

"This won't go down as his best weekend of the year," Whitmarsh subsequently admitted. "With these sorts of tyres that are very fragile, with a car that's not quite there and tricky racing, I think he did a reasonable job but he's not satisfied with himself and nor should he be.

Asked about the Raikkonen incident, the Englishman said: "I think it was robust. I've seen people weave more than that, if that's the assertion. He was doing his job, he was racing.

"You've got to be out there racing and that means sometimes you've got elbows," he added. "It's right that you've got to be robust without being dirty. And I think he was robust."