Lewis Hamilton was working overtime in Japan - Nico Rosberg

Hamilton arrived at Suzuka on the back foot after the engine failure that cost him Malaysian GP victory and left him trailing Rosberg by 23 points.

The reigning three-time champion was then involved in bizarre off-track exchanges with the media before another poor start led to him only finishing third in the race and losing more championship ground.

But Rosberg believes the problems and apparent distractions had no impact on Hamilton's handling of the weekend.

"I can tell you behind the scenes he is as focused as ever, especially after a setback like Malaysia," he said.

"He was working the longest hours I've seen him work with the engineers in many, many months trying to find those little bits of lap time, so I've seen him working extremely well and focused."

Asked whether he took any encouragement from what some Hamilton critics perceived as 'self-destructive' behaviour, Rosberg defended his title rival.

"I haven't seen any self-destruction," he replied.

"The Lewis I saw was massively motivated and focused, and anyway it's about me getting the best out of myself, and not focusing on what Lewis' state of mind is."

Despite his advantage, following a run of four wins in five races since the summer break, Rosberg is refusing to contemplate the prospect of becoming the next F1 world champion, instead maintaining his one-race-at-a-time approach.

"It's not hard [to think that] because Lewis is still my team-mate, so he's always going to be fighting, tough to beat, and there are so many races to go," said Rosberg.

"Actually, the best reasoning is that it is actually working quite well. So why change something if it's going quite well with the approach I have at the moment - which is coming into a weekend just trying to get that win."

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