MIAMI GARDENS, Fla. – Roger Federer finished with a flurry of aces and advanced to the fourth round of the Miami Open by beating Filip Krajinovic, 7-5, 6-3, on Monday.
In the last game Federer tasted aces on the first three points. An ace at the next point was overturned by a replay review, and instead Krajinovic killed the last shot in the net.
Federer ended with 14 aces and withdrew after converting only one of his first eight break-point chances.  Seed fourth, Federer improved to 14-2 this year. He made his Miami debut 20 years ago and won the tournament in 2005, 2006 and 201
On the women's side, Bianca Andreescu, who won a victory at Indian Wells, retired from his fourth-round match with a right shoulder injury while beating Anett Kontaveit, 6-1, 2-0. The three-hour Miami champion Venus Williams lost No. 2 seed Simona Halep, 6-3, 6-3. No. 3 Petra Kvitova confronted only one breakpoint and beat Caroline Garcia, 6-3, 6-3.
Andreescu, an 18-year-old Canadian, tied to the WTA leadership with 20 battle victories this year, said she felt pain and tightness in her shoulder.
"I've played so many games," she said. "I think it's just my body's way of telling me it's got enough. The doctor said it's not too serious, but the pain is there."
Andreescu said she would skip the tournament next week in Charleston , SC, but planned to play the Fed Cup on 20-20. April.
She called a medical timeout after the first set to receive treatment and received similar treatment during her third round victory over Angelique Kerber, who subsequently told Andreescu that she was the "greatest drama queen ever."
Andreescu defeated Kerber in the final of BNP Paribas Opened at Indian Wells on March 17 for his first career title. Monday's injury ended her bid to become the fourth woman to win back Indian Wells and Miami.
"I'm pretty sorry," she said. "But I really can't complain about what I've achieved."
Kontaveit no. 21 was connected to Kvitova's quarter finals, which are classified as career high no. 2 and will rise to Nr. 1 if she wins the title. Naomi Osaka, currently No. 1, lost Hsieh Su-wei in the third round.
Kvitova's fight against Garcia was interrupted by rain for more than 90 minutes, and she took advantage.
"I had a quick nap, which was really useful," Kvitova said.