Simona Halep won six titles in 2013 after entering the year with none. (Matthew Stockman/Getty Images)

Six titles. More main-draw victories in one season than she had in her entire career. A rise from No. 47 to No. 11.

Simona Halep had no idea this was coming.

"I didn't believe when I started this season that I could win six titles this year," she said. "I just wanted to play more aggressive, to play more inside the court. I did well, and I want to keep this feeling for next year."

The 22-year-old Romanian capped her breakout year last week when she won the WTA Tournament of Champions before a crowd that included her country's greatest player, Ilie Nastase. The victory put her on the verge of becoming the third Romanian woman to crack the top 10, after her manager, 1978 French Open champion Virginia Ruzici, and Irina Spirlea. Her 5-0 run in Sofia, Bulgaria, gave her 53 match victories for 2013, third most on tour, behind Agnieszka Radwanska (56) and Serena Williams (78), the only player to finish with more titles (11) than Halep.

How did Halep -- who entered the season with no titles and a 46-55 main-draw record -- finish 2013 ranked ahead of the likes of Sloane Stephens, who made the fourth round or better at all four Grand Slam tournaments, and Wimbledon finalist Sabine Lisicki? By grinding. She ruled the mid-level tournaments, which are the bread and butter for many pros.

A change in mind-set helped, too. A former junior No. 1 and the 2008 French Open girls' champion, Halep felt the burden to meet high expectations as she transitioned to the senior tour. She tightened up and put too much pressure on herself. A joylessness began to creep into her game.

"I was going on court thinking, 'I want to win this match,' and that is not a good idea," she told SI.com after winning the Tournament of Champions. "This year I tried to take pleasure in it, to relax, to just play tennis because I like this sport and I just want to improve more and more."

Halep sought to rediscover her junior-level mentality of playing without fear and fighting the urge to overthink situations.

"In juniors, I played like I do now," she said. "I wanted to be aggressive. But after [juniors], I changed some shots, like my forehand, and I was a little down in my mind. This year I started to hit the ball and believe in my forehand. My mind is more relaxed when I can hit the ball, be aggressive and move well."

The results didn't come immediately this year, though. From January through April, Halep won back-to-back matches in a tournament only once as she struggled with a lower-back problem and other injuries that affected her preparation. Halep points to a three-set loss to Lourdes Dominguez Lino in the first round of the Madrid Open in early May as the beginning of her turnaround. She was finally feeling healthy again.

"That match was incredible for me," she said. "I played three hours, and after that tournament I thought I could play at a high level."

Halep grabbed headlines a week later at the Italian Open, where she won seven matches in eight days to make the semifinals as a qualifier. Armed with an improved serve and forehand, she upset three top-20 players in Radwanska, Roberta Vinci and Jelena Jankovic. The 6-7 (2), 6-1, 6-2 victory over Radwanska in the second round was the defining moment of Halep's season.

"After [Radwanska] beat me 6-1, 6-2 at the 2011 Australian Open, I said, 'I cannot beat her ever,'" said Halep, who also had a lopsided loss to Radwanska in 2012 and another in her season-opening tournament in 2013. "It's incredible how she plays. She's very relaxed, she moves well, she hits with relaxed hands. After Rome, I said, 'If I can beat her, then I could beat a lot of players.' That was the most important moment of my career."

Halep took off from there. She won her first WTA title, on red clay in Nuremberg, Germany, in June. A week later, she collected a grass-court title in Rosmalen, the Netherlands, followed by another clay crown, in Budapest, Hungary. She added a hard-court title in August at New Haven Open, where she rolled past Caroline Wozniacki in the semifinals and Petra Kvitova in the final. And she won her last two starts of the season, defeating 2011 U.S. Open champion Sam Stosur in the final of both indoor hard-court events. Halep went 6-0 in finals, a reversal from last season when she went 0-3.

Even as she racked up titles and victories, Halep remained under the radar because of her modest performance at Grand Slam tournaments. She lost to seeded players in the first or second round of the Australian Open, French Open and Wimbledon. Seeded No. 21 at the U.S. Open, she made the fourth round before a surprising loss to Flavia Pennetta.

One objective for 2014 is play better at the big tournaments, according to her manager, Ruzici, who believes Halep has top-five talent.

"Her game is based on confidence," Ruzici said. "The main goal in 2014 is to keep this confidence. More important than which tournament she's going to win is to keep that confidence. Then the rest will follow."

With only 65 points to defend through the 2014 Australian Open, a top-10 debut is well within Halep's reach when the new season begins in less than two months.