Lewis Hamilton an track during practice at the 2018 Mexican Grand Prix.

Mercedes needs to improve “lots of different things” to vie for pole at the Mexican Grand Prix.

Valtteri Bottas in his car at the 2018 United States Grand Prix.

Valtteri Bottas could be the difference between Hamilton winning the title this weekend and Vettel taking it one more round.

Mercedes cast Valtteri Bottas as Lewis Hamilton’s wingman at the Russian Grand Prix.

Valtteri Bottas in his garage at the 2018 Russian Grand Prix.

Valtteri Bottas and Lewis Hamilton were untouchable in qualifying, leaving Sebastian Vettel third.

There’s plenty of interest in this year’s Russian Grand Prix beyond the appearance of Vladimir Putin.

Valtteri Bottas on track at the 2018 Austrian Grand Prix.

Valtteri Bottas was flawless in qualifying to better his teammate in the battle for Austrian pole.

Valtteri Bottas in his garage at the 2018 Spanish Grand Prix.

Valtteri Bottas has raised his game this year, even if the points don’t show it.

Lewis Hamilton claimed a fortunate first victory of the season at the Azerbaijan Grand Prix, inheriting the race lead after Valtteri Bottas and Sebastian Vettel’s races imploded in the last 10 laps.

Mercedes’s Valtteri Bottas topped the first free practice at the Azerbaijan Grand Prix, edging Red Bull Racing’s Daniel Ricciardo by just 0.035 seconds and blitzing Ferrari by more than two seconds.

Vlatteri Bottas congratulates Sebastian Vettel on winning the 2018 Bahrain Grand Prix.

A number-one driver needs a certain killer instinct. Bottas seems to lack it.