Nico Rosberg and Lewis Hamilton engaged in a fierce battle for last year's drivers' championship, with Rosberg's consistency seeing him lead for much of the season before Hamilton took the title in Abu Dhabi. Pre-season testing points to another year of the team-mates fighting it out, so Rosberg is leaving no stone unturned, with Mercedes highlighting his work ethic with this image on Twitter accompanied by the message: "Last man standing..."