Donald Young had made steady progress in his game coming into this year’s U.S. Open - last month, he reached his first ATP Tour-level semifinal at a tournament in Washington and recently his ranking had climbed up to a respectable No. 84 in the world, its highest point since 2008.

Yet very few could have predicted the run he is having here in New York.

The 22-year-old toppled the No. 14 seed Stanislas Wawrinka in the second round on Friday, a match that saw Young score the first five set victory of his career. Today, he took a giant leap beyond that, taking out the No. 24 seed Juan Ignacio Chela in a tight, hard-fought battlle, 7-5, 6-4, 6-3. Young moves into the fourth round of a Grand Slam for the first time in his career. With his three wins this week in New York, he also equals the number of Grand Slam wins he’s had in his entire career.

“The crowd was great today,” Young said, acknowledging the rowdy support he received that included plenty of chants of “Let’s go Donald,” and “USA, USA.

“Without them, I wouldn't have won at all.  I don't think I would have had a chance because, I was kind of getting a little fatigued.  The energy was kind of going away.  They definitely pushed me through."

In his run this week, the tennis world is finally seeing the player the tennis cognoscenti had touted for so long after Young’s impressive junior career. In 2005, Young finished the year as the No. 1 ranked junior in the world. He was 16-year, 5 months old at the time - still the youngest boy to pull off that feat. Young won the 2005 Australian Open at the ripe age of 15, and the Wimbledon juniors in 2007 at age 17.

Young credits much of his recent improvement with time spent in the off-season in Los Angeles, at a USTA training center, training with pros Mardy Fish and Sam Querry, and even hitting on occasion with Pete Sampras. "When {Sampras} was driving off after our practice, he was like, 'I expect to hear some big things from you.' " Young said. "That made me sit back like, 'Wow, Pete Sampras just said he expects me to do some big things.'  That gave me a lot of confidence and pushed me to work even harder."

Sampras’ expectations - and the rest of the tennis world's - are beginning to be met.