Sergio Perez says he has recovered from the virus that almost kept him out of the Malaysian GP, and is "100 perfect" fit to compete in Japan.
Perez revealed after last Sunday's Malaysian race that he was suffering from a virus and had contemplated sitting out the grand prix.
In the end he decided to tough it out and brought his VJM10 home in sixth place.
"I think I'm 100 percent for this weekend," Perez said on Thursday in the build-up to the Japanese GP weekend.
"I got a big virus infection and that hit me quite hard and then to recover took me quite a while.
"On Monday I was already feeling a lot better.
"Sunday was my hardest race I’ve done physically. It was so tough.
"Muscularly, it was like I had no strength at all and really, really struggled.
"I was quite lucky actually I had such an easy race. In general to hang in there was quite difficult."