Cape Town - Lewis Hamilton felt that Sebastian Vettel's demise in 2017 came because he was under "extreme pressure" and is "not afraid" of a potential fightback next season.
Vettel had the World Championship lead going into the summer break, but a series of events which were partly Vettel's fault and partly the team's fault, meant that Hamilton and Mercedes were able to land the double once again.
But Hamilton believes Vettel was tested like he never has been before and ultimately it became too much to handle.
"Seb showed more nerves this season than before," Hamilton told Stuttgarter Nachrichten newspaper.
"None of us are superman, and everyone can fail under extreme pressure."
"Some reached that point sooner, others later. It's like tennis. If Federer plays against Nadal, one waits for a small weakness in the other, because half a percent is enough."
Hamilton acknowledged that Vettel has responded well since the title slipped away and knows that his own performance has slipped, too.
But the Brit is ready to go to into battle with his fellow four-time World Champion next year.
"You saw it at the end of the season," he added. "Suddenly I had no more pressure and was not very good. I compare this season with a 100 sprint by Usain Bolt.
"He often gets a bad start but then he comes back.
"I'm assuming that he [Vettel] recovers his strength for next year, but I'm not afraid."