Unseeded Hingis, champion on the clay here in 1999, had a surprisingly easy time of it against the Russian on another day of brilliant sunshine and near-perfect conditions at the Steffi Graf [ Images ] stadium.

Dementieva had won the pair's last three matches in straight sets but only one of those was since January, when the 25-year-old Hingis made her return from a three-year retirement.

"I needed a great deal of self-confidence out there today," Hingis said.

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"I tried to make her run around so she couldn't get into a rhythm and simply tried to put the ball into the corners. She's a very strong runner and can shoot you down if you give her the chance."

Dementieva, one of six Russians in the last 16 here, had a great chance to get back into the match with Hingis on 0-40 in the fourth game of the second set. But the Swiss held her nerve, and her serve, for 3-1.

In the quarters Hingis will face either world number one Mauresmo of France [ Images ], who was in imperious form on Wednesday, or Russia's [ Images ] Anna Chakvetadze [ Images ]. They play later on Thursday.

Mauresmo beat Hingis 6-2 6-2 in the semi-finals in Doha in March, their only meeting since Hingis's return.