The striker won a competition between the lads to take to the pitcher's mound for the ceremony that signals the start of every game in the MLB.
Eddie Vedder, lead singer of rock band Pearl Jam, threw a perfect pitch before Harry stepped up to take his turn.
If there were any nerves - not least with the rest of his team-mates watching from pitchside - Harry didn't show them with an arrow of a delivery caught by Cubs' pitcher Jason Grimm.
Harry and club skipper Michael Dawson then exchanged shirts with Cubs' first baseman Anthony Rizzo before the MLB encounter against San Diego Padres.
The squad was well-received at Wrigley Field and there were noticible cries of 'Come On You Spurs' from the grandstand - no doubt from Spurs and soccer fans looking ahead to Saturday's friendly against Chicago Fire at Toyota Park!
"It was a once in a lifetime opportunity," said Harry.
"I was a little worried beforehand about hitting the floor with the pitch but it wasn't a bad throw in the end!
"I'd practised a bit at the Training Centre but I hadn't thrown a ball for a couple of weeks before tonight so I was a bit nervous but it went all right in the end.
"It's great to be here at Wrigley Field, it's my first baseball game and I can relax now!"
Below: Harry in front of the Spurs TV camera before his big moment