Valterri Bottas has admitted that he was left surprised by the pace shown by Mercedes in today's Russian Grand Prix, but has declared himself "pleased" with his podium finish.

The Williams driver finished behind Mercedes duo Lewis Hamilton and Nico Rosberg this afternoon and is now fourth in the drivers' standings.

Despite aiming to come out on top in the inaugural race in Sochi, Bottas says that he is more than happy with the momentum that he is carrying into the final few events of the season.

"We went into the race today with the mentality that we were going to fight Mercedes for the win, but their pace in the race surprised us a bit and in the end we need to be satisfied with third place and another podium," the 25-year-old told reporters.

"I was keeping pace with Hamilton at the beginning but in the middle of my first stint the rear tyres started to go away and that allowed him to create a gap. In the second stint I didn't realise Rosberg was quite as close as he was and his move caught me a bit by surprise, but he had more pace at that point anyway as my prime tyres were taking a good ten laps to switch on so he would have caught me regardless.

"I was closing in the final laps as my tyres were getting better but he had managed to create too big a gap. I'm very happy to be in fourth place in the standings and we have some great momentum heading into the US Grand Prix."

Following the US Grand Prix, attention turns to the final two races on the F1 calendar in Brazil and Abu Dhabi.