F1: Bottas laments 'terrible' medium pace

Valtteri Bottas described the grip on Formula 1's medium tyres during his final stint of the Chinese Grand Prix as "terrible" after the Williams driver limped to 10th place.

The Finn lost positions at the start when he got caught on the outside of Turn 1 as Ferrari's Sebastian Vettel and Kimi Raikkonen made contact. He made progress back through the field and at one point ran as high as second before fading in the final stint on the mediums, being passed by drivers on softer compounds.

It was the second successive race that Williams struggled for pace on the medium compound following its woes in Bahrain.

"It's a shame I couldn't gain anything from that [the Ferraris colliding]," Bottas said. "I just lost many places so it compromised my race a bit.

"It was going OK until the last stint, I was making up places and the pace was OK. But then with the medium tyres it was just terrible, terrible overall grip and especially towards the end of the stint I struggled so much."

Williams performance chief Rob Smedley admitted he was surprised with Bottas's pace, with analysis to be carried out back the factory before the Russian Grand Prix.

"He was a little bit off color at the end on the mediums, so we need to have a look because that's completely not like him," said Smedley. "He's usually very good at saving the tires and getting the most out of them, so we'll look at what happened and come back stronger for the next race.

"We made some very good decisions on car setup, which perhaps gave us a little more pace in the midfield. We still need more pace because this is not where we want to be, another two or three tenths would make a big difference."