Murray, a 21-year-old Scot whose game appears to be getting better all the time, beat Ljubicic by simply keeping the ball in play. No. 4 Murray hit just 17 winners to 36 by his Croatian opponent, but made only 15 unforced errors to Ljubicic’s 40.
The loss sullied Ljubicic’s birthday; the oldest player remaining in the field, he turned 30.
Murray has won twice already this year, at Doha and Rotterdam.
Anastasia Pavlyuchenkova, a 17-year-old from Moscow who’s beginning to look like the next Russian star, continued her run of upsets with a 7-6(8), 6-4 victory over No. 10 Agnieszka Radwanska. No. 42 Pavlyuchenkova, who knocked off No. 3 Jelena Jankovic in the second round, next faces defending champion Ana Ivanovic.
The semifinals appearance will be Pavlyuchenkova’s first in a WTA event.
Ivanovic advanced when her opponent, Sybille Bammer, withdrew because of an injured left shoulder.
“I’m very disappointed because I was playing better and better. Two years ago, I beat Ana here, so it’s frustrating for me,” said Bammer, who hurt her shoulder in practice the previous day.
She said she will have an MRI and then rest “and hope I am fine for Miami.”
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