Williams driver Valtteri Bottas has admitted his frustration with his team's poor start to the Formula 1 campaign.

Williams have failed to record a single point in the first six races, with the rookie driver fearing that the team's struggles are masking his ability as a driver.

"No-one expected that we wouldn't have any points until now because everyone was hoping we would make as step from last year," he told AutoSport.

"The things I'm doing in the car, maybe some good things are very difficult to see from outside. That's how it is now. All I can do is just do my best all the time.

"I have got positive feedback from the team and I'm still learning all the time and pace wise I've been matching Pastor, we've been very close."

Williams had 44 points at the same stage last season.