Because she is consistent and dependable while Hana Mandlikova is not, some people think Chris Evert Lloyd is boring. Winning is not boring. Evert will never make the diving, rolling, spectacular gets that Mandlikova does. But she will never let a match get away from her the way Mandlikova does, either.

Because that is so, Evert, second seeded, will play Jo Durie in the U.S. Open semifinals Friday, having beaten Mandlikova for the 15th time, 6-4, 6-3.

Last year, Evert beat her in the final, 6-3, 6-1, but the story was the same. "She is going to come up with two or three brilliant games and then you'll wonder where her shots came from because she'll make a lot of errors," Evert said. "I thought I played well. I served well (83 percent). I returned serve well and I passed well (12 winners). I was waiting for a match like this where I could feel like I'm on the road to some good tennis . . . I was trying to find my game. I found it today."

Mandlikova, seeded eighth, was brilliant one moment and made everyone, including herself, wince the next. She made so many unforced backhand errors, 21, that it is a wonder she did not start running around her backhand. One of them gave Evert break point in the seventh game of the first set. A double fault--she had four, and got in only 40 percent of her first serves--gave Evert the break.

Though Evert said the match was by far her best of the tournament, the second set was uneven. She won the first three games, then was broken twice, double faulting on break point to tie it at 3-all.

When Mandlikova played an absolutely ethereal point to begin the next game--she lunged for a backhand volley, rolled over onto her feet in time to watch it land in court--you thought perhaps her time had come. But three forehand errors and a backhand volley that landed long gave Evert a break for 4-3.

This time, there was no letting go. Evert, who has reached the semifinals of the Open each of the 12 years she has played here, held and then broke to assure the continuity of her streak.

In 14th-seeded Durie she will meet a similar, though less indulgent, player. Durie, the first Briton to reach the semifinals since Virginia Wade in 1975, beat Ivanna Madruga-Osses, 6-2, 6-2, in 51 minutes. Durie overpowered her with her serve and volley game. When Madruga struggled with her first serve, making only 64 percent, Durie pounced on the second, hitting sliced approach shots and putting away the volleys. "I was compact today," she said.

She is 0-3 against Evert, but won her first tournament two weeks ago by beating Mandlikova in the final at Mahwah, N.J., and is playing with confidence she never had before. "In Los Angeles, I came very close with her (Evert)," Durie said. "She beat me 5 and 2. Now I've gotten over the awe of playing her."

Durie, who also reached the semifinals of the French Open this year, is one of the most improved players on the tour. She was ranked 28th at the start of the year. "I've learned a great deal about myself and my game," she said. "I believe I'm a top contender. A year ago, I was still struggling. I felt I had shortcomings in my game and I didn't feel it would stand up to pressure. I have things to improve, but even if I'm playing badly they still stand up to pressure."

In England, she is the rage for her tennis, and her recent recording release, "Wimbledon Lawns" by Jo Durie and the Rackets. In the United States, she is a relative unknown, which diminishes the pressure on her. "I think, in America, they love it when those 16- and 17-year-olds come along," she said. "They dote on them. I think it's bad for the girls."

Durie is 23, and no teen-aged, two-handed backhand clone. "I'm an aggressive, powerful player and a lot of people who watch me like the change," she said.