The German admitted that another failure to perform at Barcelona on Sunday put one more dent in a championship assault.
"But anyone who writes us off," he warned, "doesn't know us.
"I'll say it again - the season is long and there is a lot of room for things to happen.
"Of course, (Spain) wasn't the best thing for the title. But we are not out of the running."
McLaren's Kimi Raikkonen soared to Circuit de Catalunya victory, but his boss - Ron Dennis - vowed to keep the champagne tightly corked.
He remarked: "Ferrari may find something, Bridgestone may come up with a better tyre.
"What you mustn't do is underestimate your competition." -GMM