Formula One needs Lewis Hamilton to have a teammate who provides a better challenge than Valtteri Bottas, according to former world champion Jenson Button.
Hamilton has dominated Mercedes partner Bottas since the Finn replaced Nico Rosberg ahead of the 2017 season. Rosberg retired after beating Hamilton to the 2016 championship.
Hamilton's form since Rosberg's decision to quit has been supreme - this year he moved past Michael Schumacher's record of 91 F1 wins and he could match the German's tally of seven world titles at this weekend's Turkish Grand Prix.
While Button has been impressed with his former McLaren teammate's recent form, he thinks he could reach an even higher level with a more competitive driver - such as Max Verstappen - in the sister Mercedes.