The Frenchman has travelled far to get to what he describes as the biggest game of his career at Wembley, where Watford could win their first-ever major trophy.
A talented teenager, he starred alongside Paul Pogba at youth level for France but two cruciate knee ligament injuries stalled his progress, forcing him to miss the under-20 World Cup in 2013 that Les Bleus went on to win.
"When you had something very hard in your career you want something very nice, and a final is something very nice," Doucoure told AFP at Watford's training ground.
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"For all the players in the squad we have different experiences, different injuries. This final is the reward that we get, so it is time to make history."
Doucoure has been a Watford player since February 2016 after a reported £8 million ($10 million) move from Rennes.
However, no sooner had he arrived than he was shipped out on loan to La Liga side Granada, also then in the portfolio of Watford owners the Pozzo family, for the rest of the season.
"A lot of people only see the player on the field and how they compete," Doucoure told AFP. "Outside the field there are a lot of things, like when I came they tell me I had to go to Granada so it's hard to accept at the beginning.
"I accepted that because I played in Spain, I played good football there. I played against the biggest teams in the world, Real Madrid, Barcelona. (It was) quite a good experience for me and when I came back here I was stronger, ready to compete for my place."
Even on his return, though, Doucoure was often surplus to requirements under Walter Mazzarri and would have been loaned to Lorient had the paperwork for the deal not missed the transfer deadline by 33 seconds.
Instead, he stayed put as Mazzarri moved on and his performances over the past two seasons, scoring 12 goals and providing 10 assists from midfield, have sparked transfer speculation linking the 26-year-old with a £50 million summer move to Arsenal, Chelsea or Paris Saint-Germain.
"Of course Paris is one of the best teams in Europe but I don't have this in my mind that I want to go to Paris," Doucoure said.
"The main thing is I want to stay in the Premier League. I think this is the best league for me for my qualities so this is my main target to stay here.
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"After, it depends what clubs come in, it depends on a lot of things but I am very open-minded."
However, he is clear that Champions League football is the target.
"Of course, I think it is a dream for a lot of players, not only me," he said. "I think a lot of players in the squad want to play in the Champions League."
That ambition comes not only from wanting to play at the highest level, but also the desire for international recognition.
Starring in the Premier League has not yet been enough to catch France coach Didier Deschamps's eye and Doucoure accepts that is to be expected while he stays at Watford.
"It is hard to get to the French national team now if you don't play in the big clubs and if you are not watched by everyone.
"Didier Deschamps said on TV 'you need to have players playing in the Champions League' so for me I know I can have the level, but since I am here, it will be very hard."
What better stage than against the Premier League champions in front of a worldwide audience at Wembley to show Deschamps and potential suitors what he is capable of?
"It's a game I can show my quality to everyone in England and France as well," he added. "All the time when you have the chance to play in front of a lot of people, you have to show your quality, to give everything. After, maybe you can get something you don't expect."
Watford will hope it is City that suffer a shock as they attempt to a land a first-ever League Cup, Premier League and FA Cup haul in English football history.
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