World championship leader Lewis Hamilton expects to have a fight on his hands this weekend, as he bids to extend his Mercedes team's unbeaten run at the Red Bull Ring race track with victory in the Austrian Grand Prix.

The German marque have won every race around the 4.3-kilometer long circuit, nestled amidst the lush alpine meadows of Austria's Styrian Mountains, since it returned to the calendar in 2014. But with relative form between teams varying almost on a race-by-race basis, Hamilton knows all bets are off this year. "It doesn't really make any difference coming into this weekend," Hamilton, 33, who won last week in France and regained the championship lead from Ferrari rival Sebastian Vettel in the fourth such swap at the top of the tables this year.