Top seed Hingis, chasing her first triumph in the Berlin clay-court event, was leading 4-1 in the second set when a heavy shower halted play.

But the sky soon cleared and the 18-year-old Swiss sealed victory. She will now face Austrian Barbara Schett, seeded 16th, for a place in the last four.

Schett, a semifinalist in Hamburg earlier this month, beat sixth seed Nathalie Tauziat of France 6-1, 4-6, 7-6 after a close battle.

Former world number one Steffi Graf had earlier recovered from a slow start to beat Zimbabwe's Cara Black 7-6, 6-2 and advance to the last eight.

Graf, returning to action after two weeks off with a foot injury, had needed three sets to move past unheralded Sandra Nacuk of Yugoslavia in her first match Tuesday.

``I played better today,'' she said after beating Black, whose brothers Byron and Wayne play on the men's circuit.

``My serve was not that good but I was more patient,'' she added. ``You need patience to win on clay.''

Graf goes on to meet France's Julie Halard-Decugis, who crushed Pavlina Stoyanova of Bulgaria 6-1, 6-0.

Arantxa Sanchez Vicario, the fourth seed, also qualified by beating Conchita Martinez 6-1, 0-6, 7-5 in an all-Spanish tie. Martinez, seeded 14th in the $1.05 million event, won the tournament last year.

Sanchez-Vicario, warming up for the defense of her French Open title from May 24 in Paris, will now face Serena Williams, the seventh seed, who beat fellow American Lisa Raymond 6-1, 7-6.

France's Amelie Mauresmo, who burst into the limelight by reaching the final here last year, fell to Romanian Ruxandra Dragomir in straight sets, 6-2, 7-5.

Dragomir, who had knocked out Wimbledon champion Jana Novotna in the previous round, will play Swiss Patty Schnyder, the eighth seed, in the quarter-finals.

Schnyder was made to work by Israel's Anna Smashnova before winning 2-6, 7-6, 6-1.