As we celebrate the 50th anniversary of the US Open, we look back at the 50 champions who have left an indelible mark on this inimitable event.

The US Open faithful have their favorites, no doubt, and they are rarely shy about cheering them on. These players tend to be either glamorous or gritty, a testament to the US Open’s embrace of New York City fashion acting in tandem with the metropolis’ hard-scrabble reputation. And they are most often home grown, the fans cheering on the U.S. representatives at America’s Grand Slam.

Then there is Kim Clijsters.

The Belgian was beloved by US Open fans long before she won her first women’s singles title in 2005 and maybe never more so than when she made perhaps the most endearing return to tennis in the sport’s history. That came in 2009, when Clijsters came out of retirement and, with precious few matches under her belt, claimed the crown, joined during the on-court ceremony by her daughter, Jada, who stole the show and nearly toddled off with the trophy, as well.

Clijsters returned in 2010 and won a third Open title, in the process running her Flushing Meadows winning streak to 21 matches in a row – albeit with a three-year absence for maternity leave and retirement interrupting victories No. 7 and 8.

That run of success stamped Clijsters as one of the Open’s all-time greats. In the Open era, only Chris Evert, Serena Williams, Steffi Graf and Martina Navratilova have won more women’s singles championships. And Clijsters’ three title runs included wins over US Open champions Maria Sharapova, Samantha Stosur, Serena Williams and Venus Williams and Grand Slam winners Ana Ivanovic, Petra Kvitova, Li Na and Carolina Wozniacki. That she surrendered just six sets in those 21 matches is testament to her quality of play.

play video 50 for 50: Kim Clijsters, three-time women's champion

But Clijsters did something more than achieve. She won hearts as well as titles, with fans rooting for her like she was one of their own (and fellow players rooting for her in equal measure). Much of that came from how she secured her hardware. Clijsters was not an instant success. She lost in the 2003 final to fellow Belgian Justine Henin and routinely fell just shy in the Slams, earning her the ignominious title of best player never to have won a major. That made her 2005 championship – her first Grand Slam singles win – that much sweeter and that much more appreciated by both the player and the crowd.

And then Clijsters was gone, retired in her mid-20s to start a family, leaving a hole in the tournament and a void on the tour. So when she decided to come back in the summer of 2009, it was celebrated. But while she was clearly a dangerous floater, few expected a second US Open title. Yet there she was, having vanquished both Venus and Serena in the same fortnight, holding the trophy in disbelief, the first mom to win a Slam since Evonne Goolagong in 1980. And just when the fans couldn’t love her more, they did.

When she played her last professional singles match, losing to Laura Robson in the second round of the 2012 Open, she was cheered again, with a thunderstorm of applause from a sold-out crowd that had grown to love an eminently lovable player, a three-time Flushing winner who showed that heart is truly what makes the champion.

50 Fact: Having come out of retirement earlier that summer, Clijsters did not have a ranking by the time the 2009 US Open rolled around. She was granted a wild card into the main draw and made the most of it, becoming the first – and, to date, only – wild card to win the US Open in the Open era. The previous best performance by a wild card came in 1991, when Jimmy Connors reached the semifinals. And the prior top run by a women’s wild card was the fourth round, achieved by Martina Hingis in 2002, Serena Williams in 2006 and Severine Bremond in 2008.