Gambill set to seize moment against Agassi.(South Florida Sun-Sentinel)

NEW YORK _ Of all the suspects who have survived the first week of the U.S. Open, no one has played with as much shocking efficiency as Jan-Michael Gambill, who seems finally to have assembled the net game that could take him to the most rarefied air on the men's tour.

No more futile waving of his racket at passing shots. No more off-balance lunges inside the service line. Or at least very few.

In three wins here, two against top players, Gambill has raised his point-conversion efficiency at net to a much higher level (75 percent) and he's going to need every bit of that, and more, to defeat Andre Agassi in the fourth round Tuesday.

Rain washed out Sunday's program, slipping everyone one day. It gave Gambill, whose ranking has fallen to No. 57, another 24 hours to contemplate how to break a five-match, 11-set losing streak against Agassi.

This is going to be one of the most important matches in his stuttering career, which last year took him to No. 14 before a bad shoulder and his usual clay-court meltdown sent him reeling.

If he does retreat, no one is going to remember that he reached the fourth round at the U.S. Open for the first time in his six-year pro career.

"I need to bring the presence I've had in these last three matches," said Gambill after converting 20 of 24 points at the net in a one-sided 6-0, 6-2, 6-0 win over No. 21 Gaston Gaudio in the third round.