The Mercedes-GP driver won his second race in F1, but teammate Lewis Hamilton could only finish fourth, falling 20 points behind Vettel in the drivers' standings.
Bottas wins Austrian Grand Prix as Vettel extends title lead over Hamilton
Valtteri Bottas did teammate Lewis Hamilton a favour as he won the Austrian Grand Prix.
The Finn prevented Hamilton's championship rival Sebastian Vettel from winning the race, thus limiting the points Vettel gained on the Briton in the title race.
Hamilton had started eighth due to a five-place grid penalty for a gearbox change, and though he fought back to finish fourth, he lost six points to Vettel, who was second, and now trails the German by 20 points in the standings.
If Vettel had won the race the gap would have been 27 points.
Bottas controlled the race after converting pole into the lead at the start, and he is now 35 points behind Vettel in third in the championship.
Daniel Ricciardo picked up his fifth successive podium as he finished third in his Red Bull Racing car, with Kimi Raikkonen's Ferrari completing the top five.
Ricciardo's teammate Max Verstappen failed to finish for the third race on the trot after being hit at the first corner by Daniil Kvyat's Toro Rosso in an incident which also eliminated Fernando Alonso's McLaren.
The next round of the championship, the British Grand Prix, takes place on July 16.