Stefanos Tsitsipas beat Casper Ruud 6-1 6-4 to win his third Monte Carlo Masters title in four years.
Greece's Tsitsipas, 25, dominated the opening stages and sealed the first set inside 36 minutes.
Norwegian Ruud fought valiantly in a tense second set, which was level at 4-4 before Tsitsipas pulled away in the final two games.
"It's been a very difficult time for me, so to be back on the podium and winning, it's amazing," he said.
The victory took Tsitsipas to seventh in the world rankings and he fell to the floor in emotion after his win.
"I am extremely grateful to my friends, family and everyone behind this journey," he added. "To win three [titles] is just unbelievable - it was a nerve-wracking game but I am extremely happy."
The success concluded a significant tournament for Tsitsipas as he also beat top-10 players Alexander Zverev and Jannik Sinner to reach the final.
He joined Rafael Nadal, Bjorn Borg, Thomas Muster and Ilie Nastase in the list of players to win three or more titles at Monte Carlo.
Tsitsipas committed to a fearless style of play, dominating on the forehand and challenging Ruud's tactics of playing deep from the court.
He broke Ruud's serve in the third game of the first set and the Norwegian, who struggled for fluency, could not recover.
The 25-year-old Ruud improved significantly in the second set and a tense seventh game lasted 13 minutes, but Tsitsipas survived three break points.
In an impressive all-round performance, he saved all eight break points he faced and converted four of his own eight break opportunities.
Both players are set to play in the Barcelona Open next week, where defending champion Carlos Alcaraz has been forced to withdraw with a forearm injury, but Rafael Nadal is set to make his comeback.
BBC