Valtteri Bottas admitted that Williams have under-performed so far this season in a car that has the potential to regularly challenge for podiums.
Bottas and his Williams team-mate Felipe Massa have both had chances of finishing on the podium so far this year but have suffered a variety of different problems resulting in a fifth place finish being their most impressive result in 2014 to date.
In the season-opener in Australia, Bottas looked like he could finish in second place before a collision with the wall led to a rear puncture, while both drivers were quick in Bahrain before tyre degradation problems compromised their races.
Massa's Chinese GP was ruined during a wheel mix-up during his first pitstop, while the Brazilian had chance of winning in Canada earlier this month before a wheel gun failure cost him pressure seconds.
In Montreal, Bottas had had issues with the brake-by-wire system and ERS that compromised his race, but despite their range of problems so far this year, both drivers remain confident that they will deliver on their promise.
"It's always been different things - we haven't been repeating the same kind of mistakes," Bottas told Autosport when asked about the problems they've had this year.
"For my car in Canada, the conclusion after the race was that we could have done a better job with the strategy, but in the end - with the failure we had with the ERS - there was nothing we could have done.
"In Barcelona we had a strong race and it was not meant to be the best track for us, so we just need to aim for better results and more points."
Massa agreed with the Finn, saying: "It was a big opportunity [to win in Canada], but we have a very good car so I hope we can be competitive again."