Serena Williams beat Maria Sharapova for the 15th consecutive time, rallying in both sets for a 6-4, 6-3 victory in the Sony Open semifinals on Thursday.

Williams, seeking a record seventh Key Biscayne title, improved to 16-2 against Sharapova and hasn’t lost to her favorite foil since 2004.

“I have always felt when I’m playing at my best, then it’s hard for people to beat me,” Williams said.

Rafael Nadal could say the same. He advanced to the semifinals by hitting a flurry of forehand winners down the stretch to beat Milos Raonic 4-6, 6-2, 6-4.

On Saturday, the No. 1-ranked Williams will try for a record seventh Key Biscayne title against No. 2 Li Na, who overcame 40 unforced errors to beat Dominika Cibulkova 7—5, 2—6, 6—3. Williams is 10—1 against Li.

No. 7—seeded Tomas Berdych advanced to Friday’s semifinals, beating Alexandr Dolgopolov of Ukraine 6—4, 7—6 (3). Berdych was the Key Biscayne runner—up in 2010.

The No. 1—ranked Nadal, who is 0—3 in Key Biscayne finals, needs one more win to get there again. His opponent Friday night will be No. 7—seeded Tomas Berdych, who advanced by beating No. 22 Alexandr Dolgopolov 6—4, 7—6 (3).

Nadal has beaten Berdych 16 times in a row over the past seven years.

The No. 1—ranked Williams won with a superior serve and better returns. She hit nine aces and broke five times, helping her rebound from deficits of 4—1 in the first set and 2—0 in the second.

Williams earned her 14th consecutive victory against a top—10 player. Her opponent in Saturday’s final will be either Australian Open champion Li Na or Dominika Cibulkova of Slovakia.

Williams first won Key Biscayne in 2002 and is the defending champion. She has worn Miami Dolphins orange and turquoise throughout the tournament and considers it her home event because she lives 90 minutes up the road.

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