NEW YORK -- Tommy Haas survived his second five-set thriller of the tournament on Monday night, narrowly squeezing past Thomas Enqvist into the fourth round of the U.S.Open.

The German again bounced back from two sets to one down to beat the 29th seed 6-4, 3-6, 3-6, 6-4, 6-4.

In the first round, he was taken to five sets by Karol Kucera.

The third seed did enough on a damp and blustery night, however, and meets Pete Sampras for a spot in the quarterfinals.

Sampras also needed five sets to beat Britain's Greg Rusedski 7-6, 4-6, 7-6, 3-6, 6-4.

"I think he won the first four matches against me," Haas said, looking ahead to the next round.

"I beat him once, in the (round robin) World Team Cup which didn't really count for me.

"But I beat him in Toronto a couple of weeks ago which was a great match. Before that, in the finals of Long Island which was also a good match. That was last year," he added. "It's nice."

Haas has a better than most record against the winner of a record 13 Grand Slam titles, having won three of their seven meetings.

"It all depends on how well he's going to serve," Haas said. "I think I am going to have to be able to serve big and hold my serves ... play pretty steady from the baseline, try to return well."

Haas had come into the fourth and final Grand Slam of the year with a sore shoulder and had been worried it may not stand up to the test of gruelling five-set matches.

"The shoulder is hanging in there actually quite well which is great," he said after Monday's victory.

"So is my arm. Overall I am very happy that I won this match, obviously. All that matters is that you come out on top at the end, so that's nice."

But the German knows the real battle begins now.

"Every match is tough," he said. "But to win a slam it starts now, the next couple of matches.

"I am playing against maybe the greatest player ever tomorrow.

"If you get through a match like that then maybe you can ask me (about winning the Open) again."