Ferrari's Sebastian Vettel has admitted he underperformed at times during the 2018 Formula One season and says he needs time to recover from an "exhausting year".
Despite a strong first half to the year, Vettel was out of title contention with two rounds remaining as he failed to match eventual champion Lewis Hamilton.
Vettel's last victory came at the Belgian Grand Prix in August and in the eight races that followed he scored just 106 points to Hamilton's 177. A combination of collisions and mistakes in France, Germany, Italy, Japan and the U.S.A. contributed to his struggles and saw him lose momentum at a crucial part of the season.