James Blake showed he was not in Shanghai just to make up the numbers when he produced a quality performance to upset world number two Rafael Nadal 6-4, 7-6 in his opening match at the Masters Cup on Monday.

The 26-year-old American, playing his first Masters Cup match, came back from a break down in the first set and recovered from a 4-0 deficit in the second to triumph 7-0 in a one-sided tie-break.

Nadal, also making his debut in the event after missing last year's season-ender through injury, started both sets well but seemed rattled when Blake would not just lie down after being broken.

World number eight Blake matched the muscular Spaniard's forehand power and showed evidence of the work he has been doing on his backhand as they indulged the crowd with some thunderous rallies in the opening match of the Gold Group.

Both players had to save break points early in the first set but the French Open champion was the first to convert one, taking a 4-3 lead when his opponent went long.

There was nothing wrong with the New Yorker's range, however, when he fired a backhand winner to break back in the next game and he held serve with ease before breaking again to win the set when Nadal netted.

Nadal raced to a 4-0 lead at the start of the second set and it looked like the contest was headed for a third.

"He was playing great tennis and I lost momentum a bit after the first set," Blake said. "It's something I've been working on, not getting down on myself. I was 4-0 down but anything can happen."

It did.

After getting himself back in touch, Blake broke Nadal when the 20-year-old was serving for the set.

There was only one man in the ensuing tiebreak and Blake sealed his third victory over Nadal in three attempts with another superb forehand down the line winner.

The victory gives Blake every chance of reaching the semi-finals as one of the top two in the group.

World number three Nikolay Davydenko takes on another Masters Cup debutant in Spain's Tommy Robredo in the other Gold Group match later on Monday.