Rain halted play for the third and final time at the US Open on Tuesday, adding to the backlog of matches at the season's final Grand Slam.

In between the persistent showers that have disrupted play for two days, officials were able to complete one match, world number one Andre Agassi advancing to the quarter-finals when Taylor Dent retired with a thigh injury trailing 6-7, 6-4, 7-5.

"It's a tough situation for everybody," Agassi said.

"It's tough for the players, tough for the fans, tough for the tournament to sort of make all the calls.

"They have a lot of experience doing it. There's a lot of variables to consider.

"I wish it was only my match they had to worry about but unfortunately it's the rest of the tournament."

Taking advantage of a break in the steady drizzle, action had resumed on five courts.

But women's fourth round matches between seventh seed Anastasia Myskina of Russia and Frenchwoman Mary Pierce and Japan's Ai Sugiyama against Italy's Francesca Schiavone that began on Monday remained uncompleted.

Three other men's fourth round matches were well under way when the rain returned with third seed Juan Carlos Ferrero of Spain leading American Todd Martin 6-2.

In other matches, fifth seed Guillermo Coria of Argentina led Sweden's Jonas Bjorkman 6-2, 2-0 and 11th seed Paradorn Srichaphan of Thailand held a 4-3 advantage over sixth seed Lleyton Hewitt of Australia.

Earlier, organisers postponed Kim Clijsters's quarter-final against Frenchwoman Amelie Mauresmo until Wednesday.

The Belgian top seed and fifth seed Mauresmo were originally due to open the day session on Ashe at 1100 (1500 GMT).

Lindsay Davenport's quarter-final against Argentine Paola Suarez, intended to start the evening session, was also put back a day.

Men's fourth round matches between Swiss second seed Roger Federer and Argentine David Nalbandian and seventh seed Carlos Moya of Spain and 22nd seed Younes El Aynaoui of Morocco were also pushed back to Wednesday.