Trimble went into the match feeling confident from his win over top seed Matthew Lucente the night before.
Trimble and Yam played some great hard rallies with excellent movement from both players.
It was Trimble though who forced the errors and played some outstanding tight shots to claim the first game 11-6.
Both players fought hard and had some great pickups and intense rallies with retrieval that was unexpected.
Yam, however, forced the ball out of Trimble's reach and took the long game 12-10 to leave the match at one set apiece.
The third game saw more high intensity long rallies with great accuracy from both players and retrieval of balls many would expect to be gone.
It was Trimble who was able to push through the pressure and reclaim the lead and the game 11/9.
The fourth game saw some excellent shots from both players and Yam looked set to clinch the fourth with an excellent roller at 10-all to give him game ball but Trimble kept his calm and managed to clinch the match 13-11.