Felipe Massa said he coped better than expected with his marathon 160 lap test session at Jerez today.
The Ferrari star is returning to racing this year having sat out half the 2009 season due to the severe head injuries he sustained at the Hungaroring last July.
He has conducted an extensive fitness programme to ensure he is fully recovered ready for his 2010 campaign, and he said he had no difficult with today's huge mileage.
"We’ve never driven 700 kilometres in just one day,” said Massa.
"Physically I feel well, I actually thought that I might be more tired than I am."
Massa added that his massive number of laps had also allowed the team to complete plenty of vital preparation work for the new season, and also shrugged off a minor problem that forced him to stop on track at one point.
"I’m pleased by the work we’ve done today, because we could test the car under all conditions," he said.
"The only stop I had doesn’t worry me at all, because we know what caused it.
"I think we’re heading in the right direction, but we’re aware of the fact that there’s still lots of work ahead of us."
Ferrari dominated last week's Valencia test, and although it did not set the same headline-grabbing lap times at Jerez, its long-run pace has impressed the paddock.
But Massa remained unwilling to predict if the team could fight for the title this year.
"For sure we can say that we’ve got a reliable car, but it’s much too early for the rest, although I really hope so," he said.
"The one who does the best work, day after day on the track and at home, wins the title.
"I’m not the most important thing here.
"What counts is that we know that we’ve got a fast and consistent car."