Sergio Perez felt confident he was back to full fitness after completing the opening practice day in Valencia.
The Sauber driver, who suffered concussion in a massive Monaco qualifying accident, had to withdraw from the Canadian Grand Prix having felt unwell in opening practice. He was replaced for the rest of that event by McLaren reserve – and ex-Sauber driver – Pedro de la Rosa.
But today Perez managed a full day of practice in Valencia with no ill effects.
"More than anything I'm happy to be back in the car," he said. "Everything went OK, I feel well and I have done a lot of work over the last weeks to get there. I picked up speed quite quickly and this is good."
Having ended up only 16th, Perez admitted his main concern was Sauber's apparent lack of performance on the Spanish street track.
"Overall it looks as if we are a bit off the pace here," he said. "We have quite a lot of work to do tonight to improve the car.
"With regard to the tires, I find it difficult to get the medium compound up to temperature. Here low grip is a general problem of the circuit. It is pretty dusty and, even with the soft tires, it is difficult to find a proper grip level. We will sort out several things and I hope for a good qualifying."