Yamaha hired Vinales from Suzuki after Lorenzo - a Yamaha rider since the start of his MotoGP career in 2008 - switched to Ducati for this season.

Vinales duly began his Yamaha stint with victory in the season-opening Qatar Grand Prix last month, having dominated pre-season testing and taken pole.

While Vinales had two seasons in MotoGP with Suzuki before switching to Yamaha, Lorenzo came to the team as a rookie following two 250cc titles - and began with three straight poles before winning in his third start at Estoril.

Lorenzo said watching Vinales's attitude this year reminded him of his early days in MotoGP.

"Somehow, Vinales' determination reminds me of myself," Lorenzo told Motorsport.com. "As I did back then, he doesn't believe in any myths.

"I used to feel the same strength and fresh determination he's showing now; a conviction about being able to win."

Vinales has so far outperformed teammate Valentino Rossi at Yamaha.

Rossi's task "not easy"

Lorenzo suggested 22-year-old Vinales's presence in the team could prove increasingly challenging for the now 38-year-old Rossi, who is now the oldest rider on the grid by six years over Aspar Ducati's Alvaro Bautista.

"It's nothing easy for Valentino to keep racing MotoGP at his age," said Lorenzo. "The second oldest rider is maybe 32, and he's 38.

"I guess when you become 38 every season is tougher than the one before; that's something Rossi recognises himself. You don't see many 38-year-olds as fast as Rossi.

"It's not something easy and even less when you have an outstanding and strong teammate like Maverick."

Having languished around the foot of the top 10 in testing and practice, Rossi made a breakthrough on the Friday in Qatar and finished third in the race.

Lorenzo suggested his long-time teammate had benefited from the uncertainty over the weather on race evening in Qatar, when a storm delayed the start and left areas of the track damp at first.

"Valentino went out in Qatar feeling very determined to make the most from such tricky conditions, something he manages better than anyone else, probably the best," admitted Lorenzo.