NEW YORK, Sept 5: Second seed Rafael Nadal wilted under the strain of a fearless forehand by David Ferrer and top seed Justine Henin maintained her recent Grand Slam mastery over Serena Williams in a wild Tuesday at the US Open.

Ferrer blasted 48 winners to shock his Spanish compatriot 6-7, 6-4, 7-6, 6-2 in a three-hour, 28-minute fourth-round match on Arthur Ashe Stadium that ended at 1:50am on Wednesday.

Henin, who knocked out Serena at both Wimbledon and the French Open, outslugged her opponent 7-6, 6-1 to reach to the semi-finals against either Venus Williams or Jelena Jankovic.

“He’s (Ferrer’s) having an unbelievable season,” Nadal told reporters.

“He’s one of the best players of the world right now. He’s a very tough player, very fast. For me, it’s not a surprise.”

The 25-year-old Ferrer, who had lost his last four matches against Nadal, clinched victory when the world No 2 hit a backhand lob beyond the baseline.

Nadal, a three-time French Open winner, who has been hampered by a left knee injury, had no answer for the heavy forehand from Ferrer.

Elsewhere on the men’s side, third seed Novak Djokovic advanced to the Open quarters for the first time with a 7-5, 7-6, 6-7, 6-1 triumph over Argentine Juan Monaco.

Other fourth-round winners included former world No 1 Carlos Moya of Spain and Argentine Juan Ignacio Chela, who will face Ferrer in the quarter-finals.

World No 1 Henin survived a set point at 5-6 before storming through the tiebreaker 7-3. Williams never recovered, falling behind 3-0 in the second set.

Henin’s win was her first over Williams on a hard court and levelled her career record against the double US Open champion at 6-6.

Williams committed 28 unforced errors but refused to give Henin credit for raising her game in the 36-minute second set.

Djokovic, 20, needed just under four hours to subdue Monaco, a 23-year-old who had never won a match at Flushing Meadows before this year.

Moya, 31, survived a courageous challenge from 19-year-old Latvian Ernests Gulbis to win 7-5, 6-2, 6-7, 6-4, while Chela outlasted Swiss Stanislas Wawrinka 4-6, 6-2, 7-6, 1-6, 6-4 to reach his first Open quarter-final.

Tuesday’s results (prefix number denotes seeding):

Men’s singles: