Berlin - Just three races into the Formula One season, and there is already friction between Mercedes team-mates Lewis Hamilton and Nico Rosberg.
The Briton Hamilton beat his German team-mate for victory at the Chinese Grand Prix Sunday as they rebounded well from a surprise defeat against Ferrari's Sebastian Vettel in Malaysia two weeks ago.
Hamilton beat Rosberg for the 2014 title in an at times tense relationship, and has also finished ahead of him in the three 2015 races to lead the championship.