Donald Young is now the No. 2 American after advancing to his first ATP semifinal in three years at the Citi Open. The 25-year-old rose 23 spots in the ATP rankings to No. 50, his highest ranking in over two years.
Young fell to his lowest ranking of No. 202 last February, but has made a slow and steady climb back up with back-to-back Challenger titles last fall and a string of good performances at the Grand Slams -- most notably, he made the third round at the Australian Open and French Open. In Washington D.C. he earned three top 50 wins over Julien Benneteau, Denis Istomin and No. 21 Kevin Anderson to make his first ATP 500 level semifinal, where he lost in straight sets to eventual champion Milos Raonic.
Young isn't the only American to make a rankings jump this week. Steve Johnson is having the best season of his career, rising to a career-high ranking at No. 54 after beating John Isner and Ivo Karlovic to make the Citi Open quarterfinals. Johnson, a former USC standout, began the season ranked No. 156, and he has made the quarterfinals or better at five tour-level events this season.
The most impressive run of form belongs to Belgium's David Goffin. Four weeks ago the 23-year-old was ranked outside the top 100. But after going on a 20-match winning streak -- he hasn't lost a match since Wimbledon -- and claiming his first ATP title in Kitzbuehel over the weekend, he jumps 30 spots to get back into the top 50 at No. 48.
• After winning his first title of the season at the Citi Open, Raonic is back up to a career-high of No. 6. He's the defending finalist at this week's Rogers Cup.
• He didn't hit a tennis ball last week, but Grigor Dimitrov rises to a career-high of No. 8 after the injured Juan Martin del Potro (down to No. 10) was unable to defend his title at the Citi Open. Andy Murray earned some top-ten breathing room also, moving up one spot to No. 9.
• The other half of the first all-Canadian ATP final in the Open Era, Vasek Pospisil, is up nine spots to No. 27. Like Raonic he's defending a significant number of points this week in Toronto after making the semifinals last year.
• 20-year-old Austrian Dominic Thiem had a mega-homecoming, making his first ATP final in Kitzbuehel. He's up now up a career-high of No. 44.