Why? "Because he has no weaknesses and it seems at the moment that Ferrari don't either," 1997 world champion Villeneuve said at the Montreal track, which is named after his father Gilles.
Canadian Villeneuve said Vettel is "the most complete driver".
He is less enthusiastic regarding news that F1 is likely to keep its V6 engines beyond 2020, saying the sport should actually "throw them in the trash".
Villeneuve argues for a return of big V8, V10 or V12 engines, or "Whatever is necessary to make formula one cars racing cars again".
He said F1 "must be an extreme sport and a place for gladiators, and that's not what they are now.
"I'm not surprised when people start to get bored," he told the German newspaper Welt.
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