McLaren's Lewis Hamilton may have blown his best chance of winning the Formula One title by failing to secure this year's championship, according to fellow-Briton Jenson Button.
"He (Hamilton) is a great driver, but there are lots of great drivers in Formula One who did not have his package," the Honda driver told the Mail on Sunday newspaper.
"What would worry me is the lost opportunity. You can't say in my sport: 'Oh well, I only missed out by a point so next year I'll go one better.' It doesn't work out like that."
Hamilton had a 12-point lead going into the penultimate race of the season in China but ended up losing the title by a single point to Ferrari's Kimi Raikkonen after a nightmare season-ending Brazilian Grand Prix last month.
"He should be sick as a dog because another chance like that might not come round again," said Button.
22-year-old Hamilton, who won four races in his rookie season, will start next year as a title favourite.