Youth got the better of experience at the Rotterdam World tournament on Thursday when 18-year-old Novak Djokovic upset Tim Henman 5-7, 6-3, 6-4 to reach the quarter-final.

Serbian Djokovic, a qualifier, dropped serve in the 11th game of the match to allow the 31-year-old former world number four to move into a one-set lead.

A superb lob from Djokovic enabled him to break the Henman serve in the second set and take the match into a decider.

World number 72 Djokovic broke early in the third set but had to fend off repeated attempts by Henman to break back before clinching an impressive victory.

"It was a high quality match which was decided on the big points," Henman told a news conference.

"He made some good returns and also a great topspin winner on breakpoint (in the second set)."

"My back felt okay during the match but I still lack confidence. All the time you expect the pain to be back," added the 31-year-old Henman, who has been struggling with injury.

Djokovic will meet Radek Stepanek in Friday's quarter-final after the sixth-seeded Czech cruised to a 6-4, 6-1 win over veteran Frenchman Fabrice Santoro.

There was an upset as Spanish third seed David Ferrer was ousted 7-6, 6-4 in a baseline battle by Belgian Olivier Rochus, leaving just two seeded players left in the tournament.

Rochus joins his older brother Christophe in the last eight after he moved through against the injured American Taylor Dent on Tuesday -- Dent retiring with a back injury.

The prestigious indoor tournament was badly hit by withdrawals before the start, including world number two Rafael Nadal [Images] and number five Ivan Ljubicic.

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