The 43-year-old is yet to stand on a single podium since returning from retirement two years ago, intensifying speculation Mercedes might need to move on for 2013.
But ahead of the 2012 season opener, the seven time world champion told the Westdeutsche Allgemeine Zeitung newspaper: "Whether I can still compare myself with my 30-year-old self, I don't know.
"What I do know is that I am still good enough to be here," the famous German insisted.
His team boss Ross Brawn, who worked with Schumacher throughout the ultra-successful Ferrari period, conceded that the record winner of 91 grands prix is now missing a few tenths.
How is he going to claw them back?
"Maybe he doesn't," Brawn told the Guardian newspaper. "Maybe he lives with it and uses his experience and knowledge to compensate."