Button: Mercedes' Chinese Grand Prix win not just down to tyres

While Button admitted he still has little idea about the relative pace of the Formula 1 field, he insisted the pace of the Mercedes - surprising as it had been on Sunday - could not be dismissed as a one-off.

The 2009 world champion also said Rosberg's maiden victory would act as a major mental boost for the German.

"It's really difficult to understand the pace of the cars - I don't know where anyone is," Button conceded.

"I think we were surprised that Mercedes had such good pace in the race, even Mercedes themselves, and then Sauber I expected them to be fighting for a podium after qualifying in China and previous race pace, but they weren't there.

"I really don't think DRS has given them [Mercedes] that much though, they're just quick; they just have a good, efficient car.

"[Rosberg's maiden win] is massive - and it has a big impact mentally. It will be a special feeling for him, but what is even more special is he knows he can come here and probably do something similar.

"You come here and nobody really knows what is going to happen - different circuit, different temperatures - but they're in a great place right now."

Button said the seemingly fluctuating form of the F1 field was down to not only understanding the Pirelli tyres, but in translating that knowledge into making them work.

"There's understanding the tyres and also being able to work with them - if you understand the tyres, which I think we do, it still doesn't mean you can make them work," he explained.

"For me I struggled on Saturday with the cool temperatures in China, and it was a little bit better on Sunday when it was warmer.

"It's not just about understanding degradation, but understanding how to get them into working range We would hope that the hotter temperatures would help - but we hope, we don't really know. It's tricky.

"Strategy is very difficult because you don't know what the pace of the cars around you is - it seems to always be different, and every race you're against someone different."