Australian Open champion Sinner powers to Rotterdam crown
The win extended the Italian top seed's unbeaten streak to 15 - including his run to glory in Melbourne - and takes him to a career-high third in the world rankings.
"We have done a really good job some weeks ago and now we did a very, very good job here," said Sinner, referring to his Australian Open triumph.
"I'm really proud of my level that I played throughout this whole week. We have been in a tough situation but we handled it in the right way."
De Minaur, seeded fifth, hadn't beaten Sinner in six previous attempts but came into the match in the form of his life and went toe-to-toe with his opponent in the early exchanges.
But Sinner's consistency and power off both wings eventually pierced De Minaur's valiant defence and the Italian broke serve at 2-2 after some entertaining rallies.
The key game of the first set came in the 10th, De Minaur eventually breaking back after saving two set points with some extraordinary retrieving.
A lengthy rally at game point left Sinner lying on the floor gasping for breath after diving unsuccessfully for a powerful backhand drive up the line from his opponent.
But the confident Sinner recovered quickly and had his own break points in the very next game, converting at the second time of asking as De Minaur ill-advisedly left a volley that dropped on the baseline.
Serving a second time for the set, Sinner this time made no mistake, closing it out to the delight of a packed Rotterdam crowd. There was no let-up in intensity at the start of the second set, De Minaur scrapping back everything Sinner threw at him and the two players trading breaks to level at 3-3.
A tired-looking De Minaur backhand into the bottom of the net gifted Sinner another break of serve in the next game and this time the Italian held serve to take him within one game of the title.
The gritty De Minaur made him serve it out and fought to the end but Sinner was ultimately too strong and finished it off 6-4.
The two are good friends off the court and former doubles partners and they embraced warmly at the net as the Rotterdam crowd gave them a thunderous ovation for an entertaining match.
De Minaur's run to the final included a pulsating semi-final against Bulgaria's Grigor Dimitrov, later describing it as his "best match on tour."
"I asked him jokingly if he's going to lose a match this year. He's playing an incredible level and just too good. I'll get you back next time!" said De Minaur.
De Minaur said he had taken "another big step in the right direction" and pledged to "fight for bigger and better things."
Sinner's path was serene, with injury-prone Canadian veteran Milos Raonic withdrawing at the start of the second set in the quarter-final and a straightforward win over local boy Tallon Griekspoor in the semis.
