Second seed Mary Joe Fernandez, No. 3 Gabriela Sabatini and No. 5 Manuela Maleeva-Fragniere, all aided by their opponents' numerous unforced errors, posted straight-set victories Friday and advanced to the semifinals of the $350,000 Virginia Slims of New England.

Fernandez recorded a 6-3, 6-4 victory over eighth seed Amy Frazier, who totaled 37 unforced errors.Sabatini, the U.S. Open champion, triumphed 6-3, 6-2 over No. 6 Helena Sukova, who made 22 unforced errors. Sabatini erred just eight times when not under pressure.

Maleeva-Fragniere triumphed 6-1, 6-3 over unseeded Mercedes Paz of Argentina, who made 27 unforced errors.

In Saturday's semifinals, top seed Steffi Graf, who is 20-0 in indoor matches this year, faces Maleeva-Fragniere in the afternoon pairing. Sabatini and Fernandez will meet in the evening semifinal.

Fernandez, who won her last two tournaments, served 10 aces against Frazier, an 18-year-old from Rochester Hills, Mich.

"I'm very happy with my serve. She returns really well, but I had big serves on the big points," said Fernandez, who also won five of her six break-point opportunities.

She described Frazier as "tough to play against if she gets in a groove. I tried to mix it up."