Lewis Hamilton says his first victory since the 2015 United States Grand Prix didn't come as a relief or justice after his tricky start to the defence of his F1 world championship.

The Mercedes driver profited from an optimum race strategy, boosted by his team asking Nico Rosberg to let the faster car past, and Red Bull's pit stop blunder with leader Daniel Ricciardo, to take his first win in nine races.

Hamilton says had the race been dry from the start the victory would have been all-but impossible but in conditions which mirrored his maiden Monaco win in 2008 the British driver took advantage of the wet-to-dry conditions for a vital win to slash team-mate Rosberg's championship advantage from 43 to 24 points.

"People have asked me do I feel relieved and said do you feel justice is done. Honestly I came here today thinking 'I've just got to go and do it', no one's going to give it to me, it's not going to come out of thin air, it's not going to just happen," Hamilton said.

"I didn't know if I could win the race today but knowing that it was going to rain definitely opened up the window of opportunity. If it was dry there was probably no chance."

Hamilton feels his victory for Mercedes at the Principality is a greater achievement than his only other win at Monaco eight years ago for McLaren, a result which ignited his first F1 title charge, and will be looking for the same impetus this year.

"As soon as it rained I knew that - from here in 2008 that anything can happen - I was just dead certain that I was going to be on it whatever the case," he said. "I think I was better today than in 2008."