Madrid had its back to the wall from the outset at Stade de France as Liverpool attempted as many shots on target in the first half (five) as it did in its previous two UEFA Champions League finals combined (two in 2018 and three in 2019).
That first-half display included two fine Courtois stops against a close-range Mohamed Salah effort and Sadio Mane drive, but the Belgium international saved his best for after the interval.
Courtois expertly denied Salah three times in the second half, the last of which was particularly impressive as he dived to his right to tip away, with Vinicius Junior nudging Madrid ahead at the other end.
The rearguard of Madrid held firm to secure a 1-0 win and record-extending 14th European Cup title as Courtois ended with a record nine saves in the final of the competition, since Opta began recording data in 2003-2004.
Courtois has led the way among goalkeepers in the competition this season, making the most saves (59) and boasting the highest save percentage of goalkeepers to make five stops or more (80.56).
The 30-year-old, speaking after the game, reflected on a productive outing on both a personal and team level.
"I said yesterday in my press conference when Madrid plays finals they win it," he said.
"And I'm on the good side of history, I saw a lot of tweets coming my way that I will get humbled today and it was the other way round.
"I needed to win a final for my career, for all the hard work, to put respect on my name – I don't think I have enough, especially in England.
"I saw a lot of criticism even after a great season that I was not good enough. I'm really happy and proud at the performance of the team, we stuck to it and when I needed to be there I was there for the team.
"We beat the best clubs in the world, together with us, you see the year City and Liverpool had, unbelievable seasons, they fought till the end in the Premier League.
"Liverpool won two cups, today they were really strong, I think I played a great game and that was the difference – we had one chance and we scored it."
Aside from a dominant personal performance, Courtois believes Madrid has shown it is the best side in Europe.
"So many years, so much work, coming to the club of my life, yesterday I already said that Madrid wins and it is like that," he said.
"Many from Liverpool and other people criticising me but we have shown who is the king of Europe.
"I've felt very good this year, I've managed the last few weeks well, and once you make the first stop then you're focused, and I took chances from Mane and Salah.
"Nobody could take away my desire to win a Champions League. For my loved ones who have passed, I was going to win a Champions League."
As for his best save, Courtois added: "Especially Salah's, I looked for it from distance, and I knew where the ball was going. It's crazy, I don't believe it.
"The referee added five minutes without anything happening, but hey, we held on."