Nalbandian reached the US Open semi-finals in September

Paradorn Srichaphan was the only remaining player who could have denied Nalbandian, but he lost in the third round of the Paris Masters on Thursday.

Nalbandian will be one of two Argentines in Houston, joining Guillermo Coria.

However, Nalbandian pulled out of the Paris event with a wrist injury and may not recover in time for Houston.

"The problem is with the tendon of the left wrist. It's painful and means I cannot play," Nalbandian said on Wednesday.

MASTERS CUP QUALIFIERS Juan Carlos Ferrero (Spa) Andy Roddick (USA) Roger Federer (Switz) Guillermo Coria (Arg) Andre Agassi (USA) Rainer Schuettler (Ger) Carlos Moya (Spa) David Nalbandian (Arg)

"I'm going to rest all this week and maybe next week."

Coria also cast doubt on his participation in the presitigious event when he pulled out of his third-round match in Paris with a fever.

"At this level, you can't go on court feeling this bad," said Coria.

"I'm going to stay here one more day and then fly to the United States to rest and recuperate for the Masters Cup and get there in my best possible form.

"It is a dream for me to play my first Masters and I need to get better for it."

The Masters Cup takes place from 10-16 November and features the top eight players in the ATP Champions Race.