Martin Whitmarsh: 'Sergio Perez needs to improve'

McLaren boss Martin Whitmarsh believes that his team have a "hard winter ahead" with Sauber driver Sergio Perez.

The Mexican driver will replace Lewis Hamilton at McLaren next season but since the move was announced, Perez has failed to score in his last five grands prix and Whitmarsh admits that the 22-year-old will need to improve ahead of his move to McLaren next year.

Whitmarsh told reporters: "He has got a lot to learn and we've got a hard winter ahead with him.

"But I'm looking forward to working with him next year."

Perez is currently sitting in 10th place in the drivers' standings.