Murray (L) and Nadal (R) Britain's Andy Murray claimed his third successive victory over world number one Rafael Nadal to win the World Tennis Tournament in Rotterdam.
The 21-year-old Scot came through 6-3 4-6 6-0 in one hour 51 minutes to win the 10th title of his career.
Nadal was struggling with a knee injury in the closing stages and, after edging the second set, he was unable to serve effectively in the decider.
"Sorry to Rafa, I know he hurt his leg," said Murray afterwards.
"It shows how good a player he is - he was still managing to beat me on one leg."
Murray too has had his injury problems this week and has pulled out of next week's tournament in Marseille to protect his troublesome ankle.
It did not appear to hinder him in Sunday's final, however, and he played well enough to suggest he could have defeated a fully fit Nadal.
The Briton went into the match with a 1-5 competitive record against Nadal but had won their last two matches, at the US Open in September and an exhibition event in January.
After a cagey start, Murray stepped up his game to break for a 4-2 lead and served out impressively.
When Nadal called for the trainer at 2-1 up in the second set, a swift end to proceedings looked possible, but it was Murray who came off worst from the break in play as he immediately dropped serve for the first time.
If that seemed to be a decisive moment, it was misleading.
Eight successive breaks of serve saw Nadal edge the set with a brilliant 10th game- that included a running forehand winner and killer drop volley, before Murray got the early break in the decider.
By now, Nadal's knee problem left him completely unable to push up on his serve and Murray took full advantage.
Nadal showed just what an incredible competitor he is two weeks ago when he fought past Roger Federer in five sets to win the Australian Open, but there was to be no repeat performance.
The bemused crowd inside the Ahoy Arena was hushed as the world number one lost the set to love.
It was a disappointing end to the match but Murray had given further proof that he poses a real threat to the very best in the game, solidifying his place as the world number four and suggesting he can go higher.