Yokozuna (=Gand Champion) Kim Clijsters and long-standing Ozeki (=Champion) Andy Roddick played their last tournament at the 2012 U.S. Open.
Kim Clijsters really had two careers. In her first, she burst on the scene as a teenager in 1999 and from 2001 was a strong and solid Ozeki, crowned by a U.S. Open title in 2006. Clijsters was slightly overshadowed by the greater successes of her Belgian compatriot Yokozuna Justine Henin. Clijsters retired for the first time in 2007, at the age of only 23 years. The second career started almost 3 years and a baby later. Clijsters returned with a bang, winning the 2009 U.S. Open in her first comeback grand slam tournament. In 2011 she obtained Yokozuna rank - unusualy late in a player's career - by winning back-to-back the U.S. and the Australian Open. While Clijsters' tennis lacked both the big weapons of the Williams sisters and the variability of Henin, she compensated for this with an athletic, sharp, agressive allround game free of any significant weaknesses. 
Andy Roddick's career took off rapidly in the early 2000s, culminating in a grand slam title - and an Ozeki promotion - at the 2003 U.S. Open. Subsequently Roddick established himself as one of the most consistent Ozeki of the entire open era, entering 14 tournaments at Champion-rank. Only the legend Ozeki Guillermo Vilas (20 tournaments) and Arthur Ashe (15) surpass him in this department. Roddick's way to further grand slam titles - and a possible Yokozuna promotion - was blocked (largely) by a certain Roger Federer; although in a memorable 2009 Wimbledon final, Roddick had the Swiss master close to defeat - supported by his trademark, powerful, near-impenetratable serve that goes down as one of the greatest shots in the history of tennis.
