The top moment of Serena Williams' wildly successful 2013? Regaining No. 1

Most recently, Serena Williams defeated Jelena Jankovic to win the China Open. (Lintao Zhang/Getty Images)

ISTANBUL -- In 2013, Serena Williams won the French Open for the first time since 2002, defended her U.S. Open crown and won a career-high 10 titles with one tournament remaining. But Williams says the highlight of her season was recapturing the No. 1 ranking. That moment at the Qatar Open in February was an emotional one for Williams, who regained the top spot for the first time since her health scare in 2011.

"I have been through so much the past few years," Williams said during her pre-tournament news conference at the WTA Championships. "I thought if anything it was a great story not only for me but for everyone just to realize that it doesn't matter what happens to you as a person, that if you just keep going and you never give up ‑‑ I mean, people say this all the time, but really if you just fight again, you can have an opportunity to survive.

"For me, I feel all those overwhelming emotions, and then to be No. 1 again, it was a great feeling and something I never expected."

After winning Wimbledon in 2010, Williams missed a year of competition for health reasons. First, a foot injury sidelined her for the rest of that season. Then, in early 2011, she was rushed to the hospital because of a pulmonary embolism. She came back last year to win Wimbledon an Olympic gold medal and the U.S. Open.

"I didn't think I would play tennis again after [the health scare]," she said. "I thought unfortunately that I just wanted to try to survive that moment and then move on. Then I ended up playing again. That definitely built a lot of character in me, and it built even more mental toughness. It made me realize I could overcome a lot of things, and [I] obviously had a lot of help, as well. All that really, really made me feel like I can do it."

Williams clinched her return to No. 1 this year when she defeated Petra Kvitova 3-6, 6-3, 7-5 in the quarterfinals of the Qatar Open. The two will face off again at the WTA Championships this week.

http://www.youtube.com/watch?v=zh6w9zxOdFY

Williams, 32, is already looking forward to what she can do next season.

"I'm still looking to improve, and what I learned most about this year is I have a lot of room for improvement, and talking with my coach over it, I'm so excited for next year just to take my game to a new level," she said.

A year ago, Williams famously said she didn't love tennis, but the hunger and motivation to improve week in and week out has reinvigorated her. Williams is 73-4 this year, and her consistency outside of the Grand Slams -- she's made the final of every WTA tournament she's entered -- has been the hallmark of her season.

"Not that I didn't [try to win every tournament] before, but it was just different, just at a different place in my life, and more than anything I enjoy playing tennis," she said. "I love being out there. Right now, I can't imagine my life without a tennis racket in my hand and playing the next event. I think maybe that makes a difference."