But the sixth seed, Marcelo Rios of Chile, who won this tournament en route to briefly overtaking Sampras last year, was overcome 4-6, 6-2, 6-2 by the 11th seed, Todd Martin.
Malisse had upset the three-times Wimbledon runner-up Goran Ivanisevic in the previous round, but Moya's greatest challenge came from trying to keep his mind on the matter at hand and off how tantalisingly close the No 1 ranking has become.
"It's always coming to my mind, even if I don't want it to," said Moya, the French Open champion, who needs only to reach this final to seize the top ranking. But I think I would be happy if every day it would happen the same, that I have this feeling if I win two matches, I'm number one."
The Spaniard Felix Mantilla, who surprised Sampras in the second round to increase his compatriot's chances of ascending to the top, had little time to enjoy his big win.
A day after sending shock waves through the tournament Mantilla went out to the American qualifier Chris Woodruff 7-5, 7-5.
Woodruff earned a quarter-final date for late last night with the seventh seed, Tim Henman, who showed his supremacy over fellow Briton and 10th seed, Greg Rusedski, with a 6-4, 2-6, 6-4 win.
Rios was playing his first tournament after several months off due to a back injury that still appears to hamper his serve and the Chilean was only able to win 58 per cent of his first serve points against Martin, who succeeded with 80 per cent of his.
"I think I can play good maybe for a set, but then I start getting a little bit tired. My back starts to pull me down a little bit," said Rios. "I think if I was serving better, I think I shouldn't have any problems to beat him in two sets."
Martin, who picked up a title in Sydney earlier this year, felt he deserved a little more credit for the outcome than Rios was willing to give him.
"I'm sure his back didn't feel great today, but I don't think I won the match because of his rustiness," said Martin, who earned a meeting with the Australian Mark Philippoussis, a 6-4, 6-3 third-round winner over the Russian Marat Safin.
Steffi Graf, who showed improved form as she came from behind to defeat the unseeded American Chanda Rubin 2-6, 6-4, 6-2 in Thursday's semi-final of the Evert Cup at the same venue, will face either Serena Williams or Sandrine Testud in today's final.Reuse content