Lewis Hamilton on Monday admitted to concerns about Mercedes’ early-season form after seeing Ferrari’s Sebastian Vettel remain unbeaten in Sunday’s Bahrain Grand Prix.

The 33-year-old defending four-time world champion said he had little idea how or why Ferrari had been able to out-perform his Mercedes team, Vettel claiming a tense win ahead of Valtteri Bottas.

It was the German’s second win in as many races this season and installed him as a clear favourite to beat Hamilton to become a five-time champion.

“I am thinking and wondering,” said Hamilton. “My thoughts are already on the world championship – I’ve lost two races in a row now and I am 17 points down after just two races.

“Obviously, the grid penalty was difficult to swallow here this weekend, but I think the team did a really good job.

“Hopefully, when we go to China for the next race, we will have a better understanding of the tyres and put up a better fight against Ferrari.

“Shanghai has been kind to me in the past so I am hoping I can bounce back.”

Vettel won Sunday’s race despite admitting he felt Mercedes had him in ‘check-mate’ when they adopted a one stop strategy.