When Arsenal spent £100m to sign West Ham midfielder Declan Rice last summer there was a suggestion in some camps that the Gunners had overpaid.
But those voices have quietened as the England international, with some brilliant performances in a more attacking position, has helped fire Arsenal to the top of the table with 10 games to go.
Maybe his biggest test yet will come on Sunday when they visit title rivals Manchester City, who also tried to sign Rice last summer and had a bid of £90m rejected.
The Gunners may be top of the Premier League - but they were in the same position after 28 games last season and fell away - so will Rice help them get over the line? Arsenal, Liverpool and City are only separated by a point in a gripping three-way title tussle.
So what has Rice changed at Emirates Stadium this season?
There have been two areas where Arsenal's personnel have changed this season compared to last term - in goal, with David Raya replacing Aaron Ramsdale, and in midfield.
Last season Arsenal's most common midfield trio was captain Martin Odegaard, Granit Xhaka and Thomas Partey.
Rice and fellow summer signing Kai Havertz, a £65m recruit from Chelsea, are the most frequent central midfield combo with Odegaard this time.
Rice has started every Premier League game since his move, with only centre-back William Saliba playing more minutes in the league than he has for the Gunners.
The England international has the third best passing accuracy for midfielders in the league for teams currently in the top six of the table (including players with 1,000 or more minutes).
His 91% passing rate is only behind Tottenham's Yves Bissouma and Manchester City's Rodri (92% each).
Current boss Mikel Arteta is the only Gunners midfielder to have a higher passing accuracy in a Premier League season (of players to play in at least 50% of the minutes).
Of central midfielders in the league to have played 1,000 or more minutes, only Rodri (14.2) has carried the ball more than five metres upfield more times than Rice (10.4) per 90 minutes.
Arsenal are creating more chances and scoring more goals and conceding fewer chances and goals per game than last season.
However, at this stage last season - after 28 games - Arsenal were on 69 points, eight points clear of City at the top, compared to 64 this season - above Liverpool on goal difference.
Former Liverpool defender Jamie Carragher, in his Telegraph column, external earlier this month, said Rice has proved to be a "bargain".
"He is not a holding midfielder. He is a complete midfielder," said the former England centre-back.
"When Arsenal travel to the Etihad, they will feel they have the equal of City's Rodri, capable of dominating the key midfield battleground.
"Should Arsenal do it, the signing of Rice will be regarded as one of the most important in the club's history - the final piece of the jigsaw turning a team of potential into champions."
In December, former Newcastle and England striker Alan Shearer wrote in a BBC column: "It is clear the Gunners have improved from last season, when they pushed City close until the final few games, and it is Declan Rice who has made the biggest difference.
"I would go as far as saying he has been the stand-out signing from the summer, and the £100m he cost from West Ham looks like money well spent.
"Rice has made the Gunners more solid and also gives them an extra little bit of bite in midfield, but everything he does on the ball is top class as well."
Rice is having more touches in central attacking positions compared to last term, aided by playing in a better team - and in a more attacking role. West Ham finished 14th last season with a goal difference of -13.
Arsenal have an average possession of 62% this season, while West Ham never managed 50% in a season with Rice.
As a result of all this, Rice is scoring more goals and assisting more for his team-mates than ever before.
His six Premier League goals and five assists are already higher than he managed in any campaign for West Ham.
Rice said of Arsenal's midfield positions: "Mikel wants his six and eight to play completely differently. When I've played eight I have been the highest on the pitch sometimes which is strange to me. I have said that I think six is my best position."
Many of Rice's defensive statistics - like possession won and interceptions - were higher last season.
And his attacking ones, such as shots and touches in the opposition box, are higher this campaign.
His contribution has grown as the season has gone on too, taking only three corners in the first 20 games - before becoming one of their set-piece specialists.
Rice added: "You look at Rodri at [Manchester] City who is probably the best, always in the middle of the pitch linking the back and the front players. The more I've played under Mikel I have got better every time."
England boss Gareth Southgate, who named Rice as captain and handed him a 50th Three Lions cap for Tuesday's friendly with Belgium, said: "It's brilliant for him. We know he's a brilliant finisher.
"We know he can play it in a more advanced role. He's improved so much in that role and working so much with his club."
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