By fielding a "hurt" Carlos Sainz alongside Alex Albon, Williams will be bolstered by a driver looking to prove wrong the top teams that turned him down.
While there is naturally a lot of interest in Lewis Hamilton's long-awaited move to Ferrari to partner Charles Leclerc, the driver Hamilton replaces has just as compelling a story, even if Sainz's move to Williams is unlikely to lead to short-term success.
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From a race- and potentially constructors' championship-winning car, Sainz will be dropped into a seat that is not going to fight for podiums in the short term, with Williams team principal James Vowles having its focus firmly on 2026 and beyond.
Sainz, who many observers expected to continue as a number two driver alongside Leclerc at Ferrari, may not have been a match for the lightning quick Monegasque on one-lap pace, but his race pace, work rate and intelligence has kept him in the game over their four years together. And he has proven that when he gets it right, he is hard for anyone to beat, as displayed during an emotional fourth Ferrari win in Mexico.
That dominant triumph further brought a bittersweetness to the surface over the prospect of having to vacate a front-running seat, as Mercedes and Red Bull also passed up on the possibility of bringing the 30-year-old into the fold for 2025.
But their loss will be Williams' gain, with Sainz explaining his "hurt" ego has made him double down on proving a point with Williams.
"I've definitely come to peace with it," Sainz told Sky Sports F1 in Brazil. "It hurt at the time.
"We all have egos. I have a driver ego, and I couldn’t understand it at the time. I still personally don’t understand some of the choices that people have made. At the same time, it creates even more of a challenge for me and makes me even more excited for Williams.
"Williams is the one that has invested in me, that backed me up from the beginning, that came to me a full year ago, and that made me super excited. I told myself: ‘I want to give these guys what they've given to me. I want to return to them this trust they have in me.’
"I can’t wait to go there and, together with them, build something good."
That fire in the passionate Spaniard's belly is great news for the Grove team, which in Sainz and Albon will have a line-up that its current performance level doesn't deserve. Vowles' compelling vision for what Williams will look like in the future, backed by owner Dorilton, plays a big part in that.
But Sainz's move isn't just motivating for himself. It will also light a match under Albon.
At Williams the Thai driver has rebuilt his F1 career, which nearly came to a premature finish at Red Bull, by single-handedly dragging its cars into various eye-catching points finishes over the past three years.
His performances have led to Vowles asserting that Albon is of world championship calibre. But while he has been one of F1's most hyped drivers in recent years, top teams don't seem to fully agree with that assessment and have too decided against handing the 28-year-old a return to a frontline seat.
What has arguably counted against Albon is his relatively weak team-mates so far, with Nicholas Latifi and Logan Sargeant offering little in the way of a consistent benchmark. That will now change with the arrival of Sainz, and whoever comes out on top of their intra-team battle will likely give their paddock image a boost in case another opportunity is there to be taken in the future.
Albon has already been challenged at Williams for the first time by mid-season debutant Franco Colapinto, who has needed little time getting on the pace in the FW46. But the experienced Sainz will take it up another notch, which Albon says he welcomes.
"People can take it two ways," Albon said on Pirelli's most recent podcast. "They could either be threatened or they can see the challenge. I definitely enjoy that challenge.
"People must probably think, 'Okay, well finally, it's someone of a high-level calibre that Alex can go against'. For me, it's like: 'Perfect, bring it on! I love that. Show people what I can do so, it's good for me.
"Everyone has a stock around the world and I need that person to go up against to show people what I can do."
But while things might get more dicey at Williams next year, Sainz - like Albon - has a history of getting on well with team-mates. He and Leclerc have come out of their four-year partnership with a healthy working relationship, and Sainz also gelled extremely well with Lando Norris at McLaren. There was some strain on his partnership with Max Verstappen at Toro Rosso, but that was driven more at a parental level.
His reputation as a team player was one reason why Williams was so interested, and Sainz also believes he and Albon will strike a solid partnership to push both each other and the team forward.
“I had a really good experience in McLaren, having this really good camaraderie with Lando," he said. "We were both pushing each other flat-out. It’s similar to Charles here, although maybe Charles has always been seen maybe as the future of the project.
"But I’ve always enjoyed having strong team mates. I think Alex is going to be a great guy to work with next year, and I think with my experience from Ferrari, I can probably help Williams to become a better team and work together with Alex to build a strong team like I did in McLaren with Lando.”
Williams will certainly be hoping that is the case and aims to benefit from their duel whoever comes out on top. But for Sainz and especially for Albon, one of 2025's most intriguing new matchups could end up being career-defining depending on the outcome.
