Jacques Villeneuve has ramped up his criticism of countryman Lance Stroll, following a difficult opening third of the 18-year-old Canadian's rookie Formula 1 season.

Before the season, 1997 world champion Villeneuve actually defended Stroll, saying that he deserved his Williams seat despite the millions in funding provided by his billionaire father Lawrence.

Stroll then finally broke through for his first points of the season in front of his home crowd in Montreal.

"I always had confidence," he told Le Journal de Montreal afterwards.

"I also know there will be nothing easy about the next races. There's a lot of room for improvement and we're working hard for more good results."

However, Stroll had actually qualified 10 places behind his teammate Felipe Massa in Canada, and Villeneuve said that was enough evidence that Stroll's struggles are beyond the pale.

"He is more than a second slower than Felipe," he told Austrian broadcaster ORF.

"Results speak for themselves. It is one of the worst rookie performances in the history of Formula 1."

Stroll is aware of the criticism coming from observers like Villeneuve, but he said in Montreal: "I don't care what people think.

"I'm happy for me and the team. The rest is noise. People who do not like me will always find excuses."

The season continues with the Azerbaijan Grand Prix in two weeks' time.