Serena Williams got the challenge a defending U. S. Open champion should expect on Sunday.

It took three sets for her to close out a victory over Victoria Azarenka. Final score: 7-5, 6-7 (6-8), 6-1. It’s the fifth Open title for Williams and her only difficult match in two weeks at the USTA Billie Jean King National Tennis Center in New York. She hadn’t lost a set in her previous six matches, but was bothered by the swirling air and Azarenka’s strong play.

“Vika’s such a great opponent; she’s such a fighter,” Williams said after the match. “It was never over until match point.” The match started with a pair of breaks as first Azarenka and then Williams failed to hold serve. In a tight first set, Williams notched the decisive break in the 11th game and then served out the set to love.

A mammoth fourth game in the third set ended with Williams breaking Azarenka to lead 3-1 and the defending champion did not look back to move within one major victory of matching Chris Evert and Martina Navratilova (both 18 majors).

Williams smashed 36 winners during the final, compared to just 17 from Azarenka, but Williams finished with 35 unforced errors to Azarenka’s 27.