Coria suffers injury scare

World number five and top seed Guillermo Coria was forced to pull out of the Heineken Open in Auckland after straining stomach muscles.

The Argentinian visited hospital on Tuesday night after aggravating an abdominal injury during his match with Nicolas Kiefer.

He was forced to withdraw from his second-round match with former champion Dominik Hrbaty and specialists advised that he should take three days' rest ahead of the Australian Open, wich starts on Monday.

Coria made a brief appearance on centre court to apologise to fans for his withdrawal. Hrbaty wasn't complaining though as he gained a walkover and will meet German qualifier Philipp Kohlschreiber.

Kohlschreiber achieved a surprise victory over sixth seed Gaston Gaudio to reach the quarter-finals.

Kohlschreiber, ranked 198th in the world, notched a 7-6 (7-3) 6-1 win over Argentina's Gaudio to force his way into the last eight, where he is the only remaining qualifier.

He faces a tougher test against Slovakian Hrbaty, who won the AAPT Championships in Adelaide last week, and is unbeaten in seven matches on the ATP Tour in 2004.

Fifth-seeded American Vince Spadea, who beat compatriot Todd Martin in the first round, beat qualifier Fred Hemmes Jr. 6-1 6-2 to set up a quarter-final match with third-seeded Gustavo Kuerten.

Spadea, playing behind a strong first serve, was in impressive form as he produced his second straight-sets win of the tournament.

Kuerten beat Alberto Martin of Spain 6-2 6-4 and reflected: "I felt very good today and I feel my game is getting stronger."

Spanish teenager Rafael Nadal fought through two tie-breaks to beat unseeded Alberto Martin of Croatia 7-6 (7-0) 7-6 (8-6).

Nadal, 17, found himself 5-0 down in the second-set tie-break before reeling off six straight points.

In other matches Gregory Carraz of France beat countryman Fabrice Santoro 6-2 6-4 and Dutchman Raemon Sluiter beat David Sanchez 7-6 (7-3) 6-3.

Carraz and Nadal meet in the last eight while Sluiter plays second-seeded former champion Jiri Novak, who beat qualifier Gilles Muller of Luxembourg 7-6 (7-4) 6-2.