Matija Pecotic
Matija Pecotic.
  • A 33-year-old real-estate investor has become a tennis star after beating a former top-10 player.
  • Matija Pecotic works full time, but plans to play in 25 professional tennis events this year.
  • Pecotic counts Bill Ackman as a mentor, and compares his game preparation to day trading.

A real-estate investor in his 30s, who counts Bill Ackman as a mentor, has become a breakout tennis star after beating a former top-10 player at a Florida tournament in February.