Williams missed the first two-and-a-half days of pre-season testing in Barcelona due to the FW42 not yet being ready, the only team to suffer such a setback. Williams began the season out of reach from being competitive. During qualifying at the season-opener in Australia, their fastest time was almost 1.3 seconds slower than the nearest competitor. In the race, Russell and Kubica finished two and three laps behind the leader respectively. The team's best result of the season came in Germany, where Kubica was classified 10th, the team's only points finish that season. However, this result only came after post-race penalties for other drivers. Upgrades came during the season with which the FW42 began to catch up to its competitors; Russell came within 0.1 seconds of reaching Q2 in qualifying for the and finished close to the points with 12th in Brazil. However, both cars would be eliminated in Q1 at every race of the season. Despite the team's lack of performance in comparison to 2014–2017, it has been confirmed that Williams have extended their engine supplier partnership with Mercedes until 2025.