 Complete the following phrase:  After pre-season testing in Jerez, Mercedes were widely considered favourites for , appearing to have reacted well to changes to regulations mandating the use of turbo-hybrid engines. Mercedes anticipated pace was realised at the season opener in Australia and Malaysia where Rosberg and Hamilton took domit victories respectively, finishing far ahead of any other teams although polesitter Hamilton retired in Australia due to engine failure. Their first intense battle for victory happened at the 