The 17-year-old American had previously verbally committed to Stanford.
The reason Wawrinka went major raspberry in the Big Apple.
You may never hit like the Hall of Famers, but now you can hit with them.
Swiss follows his US Open championship with a new title.
The Canadian win the U.S. Open Boys' title on Sunday in New York, becoming the second Canadian to win a Grand Slam junior title this season.
No. 3 seed was crying and shaking minutes before the US Open final.
"(Stan) kept his cool. I think that's what decided the match," said world No. 1.
