"After having had a good night at the Princess Grace (hospital) in Monaco, Sergio Perez underwent some further medical examinations," the Sauber team said in a statement yesterday. "The medical staff suggested to keep him in hospital for another night under observation and carry out another scan on Monday."
Perez appeared to be in good spirits, posting a message of thanks to his fans on his Twitter page and saying he expects to be back racing in two weeks at the Canadian Grand Prix.
"Thanks for your support. In this moment thanks God all ok. Can't race, but c u back in Montreal," he said. Perez lost control of his Sauber coming out of a tunnel section of Monaco's twisting circuit. The front of his car slammed heavily into the tunnel's barrier before spinning and crashing into a tyre wall.
Team principal Peter Sauber said: "We are very relieved Sergio wasn't seriously injured. Up to the accident he was doing very well in qualifying, and also better than expected as he had outperformed all his direct competitors." Technical director James Key said: "We are looking into what happened. There is no indication at the moment from the data we have seen that there was a problem with the car.
"But we have to talk to Sergio to investigate further what happened."
There were two other crashes on Saturday.
Mercedes driver Nico Rosberg and Hispania's Vitantonio Liuzzi were both unharmed after crashing in practice.