Valtteri Bottas maintains Williams can challenge Red Bull as the 'best of the rest' during this weekend's Canadian Grand Prix.
At the previous race in Monte Carlo, Red Bull's Daniel Ricciardo finished on the podium whilst Bottas' Williams team-mate were the only of the Grove team's car to reach the chequered flag, in seventh place.
Bottas' race was ended after his Williams encountered a problem with the Energy Recovery System that resulted in engine failure, but the Finn remains confident that they will perform much better in Montreal.
"I think we can still fight [Red Bull]," Bottas told Autosport.
"It's not easy - they are really improving, [but] Monaco was probably their strongest place of the season.
"On paper, Monaco was one of the more difficult tracks for us. We just need to keep working on the updates.
"In theory Canada should be one of the good ones for us [with] long straights.
"We know in Canada it can be cold and sometimes people struggle with getting front tyres up to temperature, so we really need to take some action.
"We know the issue, so we are now looking to solve it."
Rob Smedley, the Williams Head of Vehicle Performance, revealed that the team has put in a substantial amount of work into solving the problems they've had with rear grip, and believes they will see the effect of those efforts in Montreal.
"In the first three races it was all about traction, traction, traction, and we've worked incredibly hard in lots of different areas to get around that," Smedley said.
"The teams were a little under-prepared for the front-tyre warm-up issues that we faced in Monaco - we could have done a better job in qualifying with that.
"[But] the positive is that we appear to be making inroads into the traction issues, which is a difficult problem to solve.
"Every cloud has a silver lining and I'm happy with that."