SHANGHAI - 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.

James Blake of the US celebrates his 6-4, 7-6 victory over Spain's Rafael Nadal at the Tennis Masters Cup in Shanghai. [AFP]

The 26-year-old American, like last year's winner David Nalbandian the final player to qualify for the tournament, 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 tiebreak.

"I'm not one of the last guys, I actually am 'the' last guy," Blake said after his first Masters Cup match. "I'm the guy that's supposed to be the easy matchup...which doesn't help my confidence too much. But I'm just happy to be here."

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.

Spain's Rafael Nadal hits a forehand return to USA's James Blake at the Tennis Masters Cup in Shanghai. Nadal's Masters Cup hopes have taken a blow when he was handed a shock straight-sets defeat by Blake. [AFP]

"The problem is not my game because I was playing very good...But in the important moments I lost my confidence," Nadal said.

World number three Nikolay Davydenko of Russia beat a third Masters Cup debutant in Spain's Tommy Robredo 7-6 3-6 6-1 in the other Gold Group encounter.

Nikolay Davydenko of Russia hits the ball during a match against Tommy Robredo of Spain at the 2006 Tennis Masters Cup tournament in Shanghai November 13, 2006. [Reuters]

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.

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.

"That was something I'm really proud of, to get down four Love against one of the best players in the world and not hang my head, not try to change tactics, not do anything outside of my comfort zone, keep playing my game and see if I can be on top at the end," Blake said.

SUPERB FOREHAND

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.

"I don't know if I match up well with him or I just happen to play some of my best tennis against him," said Blake.

The victory gives him every chance of reaching the semi-finals as one of the top two in the group, while Nadal will need to win his next round robin match.

"The problem is not the tennis," Nadal reiterated. "So the problem is a little bit confidence. Win one of the matches, all changes, no? So I hope I win the next after tomorrow."