The Olympic champion Elena Dementieva, has breezed into the quarter-finals of the U.S. Tennis Open with a straight sets win over mistake-prone Li Na of China.
The fifth-seeded Russian, handicapped in the past by a weak and unreliable serve, dropped serve only once against the 36th-ranked Li and lost just 13 points in all from the service line.
Dementieva, the Open runner-up in 2004 and two other times a semi-finalist at Flushing Meadows, will meet 15th seed Patty Schnyder of Switzerland in the quarters.
