By Alastair Himmer
But fifth seed Murray, beaten by Roger Federer in last year's final, will not be underestimating Nadal's conqueror David Ferrer when they meet in Friday's semi-final, despite the Spaniard's cause being aided by an injury to his opponent.
The winner faces Serbia's Novak Djokovic in Sunday's final after the third seed knocked out defending champion Roger Federer 7-6 7-5 6-4 in the first semi-final.
Ferrer's 6-4 6-2 6-3 win over world number one Nadal came mainly as a result of a hamstring tweak suffered by his compatriot after just three games.
However, the seventh seed remains unbeaten in 2011, having won a warm-up tournament in Auckland, and even a fully fit Nadal would have had his hands full.
"David's playing a fantastic tournament," Nadal told reporters. "If he keep playing like this, he has a good chance.
"I would love him to win the tournament. He's a fantastic guy and a good friend."
Murray, who also lost to Federer in the 2008 U.S. Open final, played arguably the tournament's best tennis in blowing Austria's Juergen Melzer off court in the fourth round.
He dropped his first set of the year's first grand slam against Ukrainian Alexandr Dolgopolov in the quarter-final but Murray never looked troubled.
Iron man Ferrer takes no prisoners, hitting bombs off both wings, and is one of the fittest players in the men's game, with a 3-2 career record over Murray.
So cock-sure were the world's press Murray would be facing Nadal on Friday, no one bothered even to ask about Ferrer, whose progress through the draw had gone largely unnoticed.
The Briton thrashed Ferrer 6-2 6-2 in their round-robin match at the World Tour Finals but Ferrer will have nothing to lose in only his second grand slam semi-final.
He is likely to come out swinging, drilling balls to the corners, pushing Murray to his limit and daring him to slug it out toe-to-toe, which the Briton can ill afford to do.
"It's just another match," said Ferrer, one of the best returners in men's tennis. "I will fight, like every match of my life. Andy is a top player but I am confident."
(Editing by John O'Brien and Tom Pilcher)