Grosjean has raced in F1 alongside Hamilton throughout his career, joining the Briton on the podium in three of the 10 times that the Frenchman has taken to the rostrum in his career.
Hamilton secured his sixth world title in 2019, moving onto 84 grand prix victories in the process, with Michael Schumacher's all-time records for both world championships (7) and race wins (91) in sight.
With much of the end-of-season talk focusing on where Hamilton stands among the all-time greats in the sport, despite continuing his career, Grosjean believes his contemporary is deserving of his spot among the greatest names ever seen in F1.
He said: "I think Lewis has been doing an incredible job, as well as Mercedes. You can't be a world champion if you don't have a good car.
"It's been a good combination. He's definitely in the top five drivers. It's very hard to compare, you got so many in there.
"You've got [Juan Manuel] Fangio, Schumacher, [Ayrton] Senna, Lewis, [Jim] Clark... there's so many and that's the problem. It's very, very hard to say who is going to be in the top five. But he's doing an incredible job."
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