Serena Williams takes on Agnieszka Radwanska tonight in the semi-finals of the 2013 Sony Open in Miami (01:00 GMT start).
Williams continued her progress through the Miami Masters 2013 draw on Tuesday, pulling back a 5-2 second set deficit to clinch a 6-3 7-6 win over Li Na in the quarter-finals.
When Serena was trailing in the second it looked like another three-setter could be on the way for the world No. 1. Things then got worse as a hip problem seemed to slow her down. But the injury turned out to be a minor one, leaving her with plenty of energy for a big victory leap after she clinched match point.
World No. 4 and defending champion Radwanska was pushed in the last eight by Belgium's Kirsten Flipkens. The thirtieth seed had threatened an upset by taking the first set and being neck and neck in the second at 4-4. Aga managed to finally break down Flipkens at this point, and went on to win the match 4-6 6-4 6-2.
Looking ahead to today's semi-final, Serena will surely be considered the favourite. She holds a 4-0 head-to-head record against Radwanska and has dominated past meetings between the pairing.
Even so, Radwanska is continually improving so it will be intriguing to see what she brings to the table. A win against the world No. 1 would be a landmark achievement for the Pole.
Prediction: Williams in three.