ST. POLTEN, Austria, May 20 (UPI) -- Austrians experienced mixed results Thursday in the quarterfinals of the International Raiffeisen Grand Prix.
Jurgen Melzer, the top-ranked Austrian who has climbed to a career-high 55th in the world, got past Belgian Olivier Rochus, 4-6, 7-6 (7-5), 6-2, to reach his second semifinal of the year.
But 20-year-old Daniel Koellerer, who was making his ATP Tour debut, fell to Xavier Malisse, 6-4, 3-6, 6-1, in another Austrian-Belgian matchup.
Sixth seed Daniel Sanchez of Spain advanced when No. 3 Nikolay Davydenko of Russia, the runner-up here last year, retired with a pulled chest muscle after the players split the first two sets.
In the semifinals, Sanchez takes on No. 8 Filippo Volandri of Italy, who ousted Romania's Victor Hanescu, 6-4, 6-3.
In Friday's other semifinal, Malisse faces Melzer, who won earlier this year at Boca Raton and reached the quarterfinals last week at the ATP Masters Series event in Hamburg.
