NEW YORK - No player had gone so long between stints at No. 1 in women's tennis.

More than five years after she last held the top ranking, Serena Williams officially regained the distinction Monday hours after winning the U.S. Open for the third time.

It had been even longer since her last Open championship - six years. And though it was her ninth Grand Slam title, it was just her second since capturing the Australian Open in early 2005.

Williams beat Jelena Jankovic 6-4, 7-5 in the final and didn't drop a set the entire tournament. She figures many doubted that she'd ever climb back on top of the tennis world as her ranking plummeted all the way to No. 139.

“Oh, yeah,” she said Monday. “I think a lot of people, probably everyone thought (that). I always felt that I can be No. 1 if I really put in the effort.”

Williams looked relaxed during interviews at the ESPN Zone in Times Square, dressed in a red dress with a pink shawl. She couldn't wait to get some sleep - she'd managed only about an hour over the previous 24.

After making the finals at two straight majors - she lost to sister Venus at Wimbledon - she likes the consistency she's finally showing.

“I enjoyed the journey because it wasn't overnight,” she said. “It wasn't like it just happened.”

Venus, who gave Serena her toughest test of the tournament in the quarterfinals, cheered from the stands Sunday. Afterward, Serena said, her older sister told her, “I'm so happy that you won. You deserved it. No one deserved it more than you, and that's why you won.”

Serena replaced Ana Ivanovic atop the rankings. Ivanovic dropped to No. 3 after losing in the second round, while Jankovic remained at No. 2.

It's been almost a decade since Serena won her first Grand Slam title at the U.S. Open in 1999. Her goals at the time, she recalled, were to win the other three majors and to ascend to No. 1.