The woman who has changed the face of the team has also, above all, succeeded in 'making' all her players believe in their abilities.
On the pitch at the José Alvade stadium at the final whistle, Slegers shunned the cameras. No question of celebrating with the players. The Dutch coach prefers to let them celebrate amongst themselves, with the fans.
She has a whole staff to congratulate, who form a hurried circle around their boss. Everything went according to plan, although she admits: "You can have all these ideas in your head and show videos and animations, use your tactics board, do it in training... But when the time is really right, you have to execute it in the Champions League final."
The plan worked and Slegers, 36, praises her players for making "all the right decisions" on the pitch. From her bench, she also turned the match on its head.
In the 67th minute, the Arsenal coach brought on Beth Mead and Stina Blackstenius. Seven minutes later, Mead fed Blackstenius in the box, who slotted past Cata Coll to make it 1-0.
"I was joking with Beth after the game, saying: 'I told you, give the ball to Stina and she'll score'," she told DAZN at the final whistle. Words that testify to her confidence in her new players, but also in the environment in which they evolve.
Believing in your strengths, in the team
"What we've tried to do since I arrived is to create an environment conducive to the players' performances, to believe in each of them, to give them a sense of responsibility and to identify their strengths," she explained before the match, not wishing to comment on whether or not she had succeeded in developing each of her individual players during the season.
When she was appointed Arsenal interim coach on October 15th, the Gunners were coming off two defeats to Chelsea and Bayern Munich and a 0-0 draw with Everton.
"We were really on the wrong track at the start of the season. And she came and just gave the team a lot of confidence. And I think that's what we needed. We just needed to believe in what we were capable of doing. Everything was there, we just had to do it together," recalled Emily Fox in the mixed zone after the victory.
"So much has happened this season and there have been so many difficult moments. We've always fought and our belief has grown every day of the season," added her coach. "Confidence", "belief", "faith" and "conviction" are the words most used by the Arsenal players at the end of the season.
"Belief is something we've talked about a lot as a team this season," admitted Alessia Russo before the match. I'm a firm believer in our team, and given our track record and the performances we've put in, we know what we're capable of."
Arsenal's mental strength has been worn down, but it has also been nurtured through a series of remontadas: a 3-0 victory in the Champions League quarter-final second leg against Real Madrid after a 2-0 defeat, a 4-1 victory over Lyon at Groupama Stadium in the semi-final after losing 2-1 at home.
An eye for detail that makes all the difference
Arsenal are a resilient team. They are the first team in the history of the Women's Champions League to have won the competition by going through all the qualifying rounds, from a 6-0 win over Rangers at the very beginning of September to this 1-0 victory in the final.
"If you put everything into perspective, how far we've come this season, getting ourselves into a position to play in a final, it's a lot of hard work," Slegers humbly replied on the eve of the match.
But there were also tactical reasons why the Londoners were able to go all the way in this competition. "We've found many different ways to win this season," summed up Russo before the game.
"It was a season full of ups and downs, but full of lessons learned." Captain Kim Little, for her part, emphasised her coach's "attention to detail.
"Renee, our assistant coach Aaron, and our staff, Romel, Kelly and Chris Bradley (set-piece coach), really form a machine that works well. They give us the right information to be able to play games like we did today."
In midfield, for example, Little received information on what the strengths of Patri Guijarro, Alexia Putellas and Aitana Bonmati were in front of her, how they exploited their strong points, what their preferred passing lines were, the orientation of their bodies.
And Slegers praises the way in which each of them handled them: "The players received so much information before the match and they applied it and transferred it so well on the pitch that it was an incredible performance on their part."
Continuing to make history
"We are a special team who have quality players but who are willing to work for each other. That's the key. We're hard to defend and we fight for each other. That's something you won't find in a lot of teams," adds Fox.
It is this defensive solidity and this compact block capable of constant pressure, which Wendie Renard already praised after the elimination of Lyon, that has enabled Arsenal to go all the way in this increasingly demanding competition in women's football.
And Renée Slegers knows just how important it is to see this title return to the Emirates Stadium, 18 years on: "I was at the club in 2007 (a post-training season before returning to the Netherlands) , so I have some idea of where the club comes from... There are so many people who have been involved for so long that I'm just a tiny part of it."
The Dutch woman, who has signed a contract with Arsenal until 2027, wants to continue making history: "This team still has a great future ahead of it and that's what's most frightening. The girls are going to leave for the national team. There's the Euro (in Switzerland in July), they'll be back and I'm already looking forward to doing more with them."