In tennis, the most prestigious players are those who win Grand Slams. The next best? On the women’s circuit, it’s Caroline Wozniacki, the 27-year-old from Denmark who’s now ranked second in the world.

Of all the women in tennis, no non-Slam champ has been as good as Wozniacki, who played in her first Grand Slam final in 2009 and is now in the Australian Open semifinals. She has a 541-223 record, according to the WTA, which gives her a winning percentage of 71 percent. If any Slam-less active players compare to Wozniacki, it’s Simona Halep and Agnieszka Radwanska, whose highest career rankings were No. 1 and No. 2, respectively, and who each played in at least one Grand Slam final. But Wozniacki’s overall accomplishments are more impressive, as she’s won more WTA singles titles and put up a better overall win percentage.

There have only been a handful of female players in the Open era of tennis history to win as much as Wozniacki has without lifting a Slam trophy. To measure this, we looked at the net wins (wins minus losses) of all players since 1968 through last year’s U.S. Open, and then found the point in their careers where they had the most net wins but zero Grand Slams. Only Pam Shriver, Helena Sukova and Zina Garrison — all of whom played primarily in the 1980s — reached a higher mark than Wozniacki. While Sukova’s career may be the most disappointing — she lost two Australian Open finals and two U.S. Open finals — Wozniacki has won more titles than any other player on this list.

The best without a Slam Female players with the most net wins (wins minus losses) at any point in their careers when they had not won a singles Grand Slam, 1968-2017 Career Peak Net Wins Highest Singles Rank WTA Singles Titles Slam Finals Pam Shriver +347 3 21 1 Helena Sukova +330 4 10 4 Zina Garrison +327 4 11 1 Caroline Wozniacki +313 1 27 2 Jana Novotna* +298 2 24 4 Agnieszka Radwanska +293 2 20 1 Manuela Maleeva Fragniere +290 3 19 0 Elena Dementieva +257 3 16 2 Wendy Turnbull +249 3 9 3 Jelena Jankovic +245 1 15 1 Through 2017 U.S. Open. Main draws only.

*Peak set during a Grand Slam tournament the player ultimately won. Sources: Tennis Abstract, WTA

Wozniacki may yet win a Slam, earning her way off this list much like the late Jana Novotna did. The Czech player had peak net wins of +298 before she finally broke through at Wimbledon in 1998 and won her first singles Slam at age 29. She would retire the following year. More recently, Kim Clijsters was at +239 net wins when she finally won a Slam at the 2005 U.S. Open — her fifth finals appearance.

Wozniacki can perform at her best just about anywhere. The most difficult surface for her has been grass, but she still managed to reach the fourth round of Wimbledon six times in her career, including last year. At the French Open, she twice reached the quarterfinals. Her present run to the Australian Open semifinals ties her best there. The most competitive Wozniacki of all showed up at the U.S. Open, where she lost two finals, one to Clijsters and the other to Serena Williams, who has won 23 Grand Slam singles titles in her career.

Wozniacki’s Grand Slam drought seems unlikely, especially when she’s compared to her rivals. Others with thinner resumes already have won Slams. Take Garbiñe Muguruza, who has won two Grand Slam titles but has a lower winning percentage than Wozniacki. The same can be said of Petra Kvitova, who won twice at Wimbledon. Perhaps most improbable of all: Jelena Ostapenko, who won her first Grand Slam title at last year’s French Open. She was 20 years old at the time and had never made it past the third round at a major before winning the title.

So why hasn’t Wozniacki won? She is hardly a choker. The main reason, it seems, is that her tennis is oriented more around defense — sprinting and hitting medium-pace shots — than offense. But in tennis, defensive players can get into trouble when they run into someone with a hot offensive game — which is nearly impossible to beat. Take Serena Williams, who has a better, and more consistent, offense than anyone in the game. Wozniacki has played Williams 11 times and lost 10 matches, including two at the U.S. Open (a semifinal and a final). Wozniacki has lost to Venus Williams seven times and beaten her only once.

At the Australian Open, Wozniacki has her best chance yet to end her Grand Slam title drought. She’s already managed one miracle. In the second round, she beat the unseeded Croatian Jana Fett, 3-6, 6-2, 7-5. Wozniacki trailed 5-1 in the third set and faced two match points before winning six straight games. “I felt like I was one foot out of the tournament,” Wozniacki said.

If Wozniacki reaches the final, she’ll be playing against Angelique Kerber or Halep. Over her career, she’s 5-8 against Kerber and 4-2 against Halep. Either opponent would set up a classic match, giving her an excellent chance to go from runner-up to champion. And whether she wins or loses here, there is a record that Wozniacki is very likely to break soon. If she takes over the No. 1 ranking, the gap between the last time she was the WTA’s top-ranked player and this time would be the longest stretch since the rankings were introduced in 1975. It’s not worth a Grand Slam title, but it’s not bad, either.