Carlos Sainz has scored only a point since joining Williams from Ferrari but team boss James Vowles says the Spaniard is already delivering beyond expectations and they are getting more than they paid for.
Former champions Williams are fifth overall ahead of this weekend's Bahrain Grand Prix and their 19 points from three races is more than the 17 they took from the whole of last year.
While Thai teammate Alex Albon has been the major contributor, with three successive top-10 finishes, Vowles' said the influence of 30-year-old Sainz had been clear from the start.
"I think we’re getting more than I paid for (him)," the Briton said, adding that performance could be assessed in and out of the car.
"Our car has a very different style of adapting to it than the Ferrari. He's getting there," said Vowles. "He'll be on the money very shortly.
"The car is faster thanks to the work and effort, the work ethic he's put in, and how he really develops with the engineers.
"That's why Carlos was my number one target. It's because he's absolutely brilliant at developing teams, and he’s already bringing that to the table."
Sainz, a four-times race winner now with his fifth Formula One team, joined Williams after losing his place at Ferrari to seven-times world champion Lewis Hamilton.
His sole point came in China after he was promoted from 13th when the two Ferraris were disqualified as well as Alpine's Pierre Gasly.
Vowles referred to the Spaniard as a "part-time strategist", a team player whose tactical nous and support for Albon was also contributing to their success.
"He doesn’t have any politics in him whatsoever. He just wants the team to be quicker," he added.
The boss said Albon, who has qualified in the top 10 at every race, was undoubtedly a better driver than last season when Williams finished the campaign ninth of the 10 teams.
"You saw a step from him every single year, and this year he’s really not putting a foot wrong. I can't fault anything that he's doing," he said.
"It’s absolutely on the money in terms of delivering. He knew he had to step up with Carlos in the car, and he has."