Mercedes team boss Toto Wolff expects the competition among Formula One's top teams to be closer in 2018 than it was in 2017.
Mercedes has won the last four drivers' and constructors' championships and enters 2018 as the favourites for both titles. However, after three seasons of utter domination between 2014 and 2016, the German manufacturer faced serious competition from Ferrari last year and only took control of the drivers' championship when Sebastian Vettel hit a run of reliability issues towards the end of the season.
Red Bull also emerged as a genuine challenger for race victories at the end of last season and Wolff expects at least three teams to be in the running for the championship in 2018.