Serena Williams has set up a semi-final date against world number four Agniewska Radwanska at the Sony Open in Miami.
The American world number one hasn’t dropped a set all tournament and continued that run with a 6-3, 7-6 (7-5) win over China’s Li Na on Tuesday.
“It’s good to be able to at least come back,” Williams said. “I like to believe that I try to be a solver. I just try to do things different if something is not working.
“She played such a good tie-breaker. It was important for me to win that.”
World number five Li said Williams was the world’s best female player.
“She’s best player in the world,” Li said. “If you couldn’t hold, she never give you chance again.
“I still have to see the positive way. I played well so I should be try to be ready for clay court season.”
Radwanska progressed after defeating Belgium’s Kirsten Flipkens 4-6, 6-4, 6-2 in her quarter-final.