Nico Rosberg says he will be on 'maximum attack' at the Austrian Grand Prix while singling out the Williams team as the biggest challengers to Mercedes.

The German driver is looking to fight back in Austria after failing to overcome his team-mate Lewis Hamilton in Canada and he now holds a 17 point lead in the F1 drivers' standings.

"Canada was really lost for me on the Saturday. Not getting everything together in qualifying hurt my chances big time," Rosberg said. "But I had the pace and that's a big positive to take forward and go maximum attack in Austria."

The Mercedes man will be hoping for a repeat performance from 12 months ago when he grabbed victory at the Red Bull Ring. Rosberg is expecting the usual tussle with Hamilton but has also picked out the Williams duo of Valtteri Bottas and Felipe Massa as his strongest competition for victory in Spielberg.

In 2014, Massa stormed to pole position as the Mercedes duo faltered in qualifying and Rosberg had to fight with the Williams duo for the win. The Red Bull Ring circuit places significant importance on the power units due to its high speed and flowing nature and the German feels race set up needs to be perfect to combat the improvements made by Williams.

"Of course, we didn't have the ideal start in qualifying - but we nailed it on Sunday and it was great to get the win," he said. "I'm sure we'll have some tough competition here once again with Williams and probably some others too.

"It's a circuit I really enjoy driving and the crowds are unbelievable, so I'm looking forward to getting back out there and having a good battle. Of course, it's a home race for Niki and Toto, too, so we'll need to be on our best form for this one."