NEW YORK -- Corina Morariu, playing in her first Grand Slam tournament since starting cancer treatment in May 2001, teamed with Kimberly Po-Messerli to reach the U.S. Open's doubles quarterfinals.

Morariu and Po-Messerli rallied from a set down to beat the Russian pair of Evgenia Koulikovskaya and Ekaterina Syssoeva 5-7, 6-1, 6-3 Monday night in the third round.

To get to the semifinals, the Americans will have to beat either third-seeded Cara Black and Elena Likhovtseva or 16th-seeded Maria Emilia Salerni and Asa Svensson.

The 24-year-old Morariu lost in the first round of singles to Serena Williams.

Before Morariu's illness, her highest singles ranking was 29th, and she was No. 1 in doubles for part of 2000. She and Lindsay Davenport won the 1999 Wimbledon doubles title, while Morariu claimed another Grand Slam trophy at the 2001 Australian Open, in mixed doubles with Ellis Ferreira.

Four months later, Morariu was diagnosed with leukemia and went into the hospital for four courses of chemotherapy. Morariu now takes chemotherapy pills daily.