Lewis Hamilton loses his edge when things do not go "perfectly", according to former Mercedes team-mate Nico Rosberg.

A technical glitch saw reigning world champion Hamilton lose out to Sebastian Vettel in the season-opening Australian Grand Prix, while he received a five-place grid penalty in Bahrain for an unscheduled gearbox change and finished fourth.

Mercedes dropped the ball by failing to change tyres behind a safety car in China last weekend, something Red Bull capitalised on to get Daniel Ricciardo the win.

Rosberg believes Hamilton can struggle when faced with such adversity, but backed the Briton to bounce back emphatically.

"He was really struggling and didn't know why," said the former world champion on his YouTube channel.

"When it doesn't go perfectly, he starts to lose that edge a little bit and a touch of motivation and then just struggles for a while.

"Those are the races where as an opponent in the championship you have to maximise … because Lewis always comes back and when he comes back he comes back so damn strong that he's almost unbeatable."

Max Verstappen's crash with Vettel brought the safety car out in Shanghai and the Dutchman dropped from fourth to fifth courtesy of a 10-second time penalty.

Rosberg feels Verstappen needs to curb his aggression and risk-taking if he is to become a future champion.

"He's one of the big talents and has a great future, but driving like he is at the moment he's not going to be world champion because [he makes] so many mistakes, I think five mistakes in three races - five major mistakes. It's too much," he said.