She’s not retiring. The German won the U.S. Open Saturday, defeating 10th-seeded Czech Karolina Pliskova — who’d beaten both Williams sisters in the tournament — in an unusually competitive final, 6-3, 4-6, 6-4. The accomplishment cemented Kerber’s new No. 1 status after Serena Williams’ semifinal loss to Pliskova. It also made Kerber the first German to win the U.S. Open since her idol, Steffi Graf, did in 1996. And despite being the oldest player to first attain the top ranking, she’s not about to rest on her laurels.