The students progressed to the final – the competition is now restricted to East of Scotland League clubs outwith the Premier Division – after beating first division conference X side Bo’ness Athletic on penalties after a 0-0 stalemate over 120 minutes on Saturday.
It came a month after Heriot-Watt won the Queen’s Park Shield against Stirling University, making it a productive season for Heriot-Watt.
Koya said: “I’ve been here for six years now and the ultimate goal is to develop players. Through that, we try to do things a certain way and play through the lines and the tactical approach we take is something I am a big believer in.
“I thought the players not only stuck to our disciplines really well in terms of tactical shape, but the sheer effort they put into the tie against a strong opponent was outstanding.
“The bravery we showed on the day was something you can’t teach, that is down to the character of the group.”
Captain Craig Smith was sent off in the second-half, but Koya’s side held a Bo’ness side sporting 55-goal hitman Tiwi Daramola up top.
Koya added: “Bo’ness are in conference X but have so much quality throughout their team and without a doubt they are up there with the best sides in all of the conferences at the moment.
“We did our homework on both of them and our shape really constricted how they attacked, we closed down any space straight away and were compact.
“For our team to come to their home ground and play the way we did, and then take it to penalties while down to ten men was really special.
“It’s a brilliant day for our club and certainly one of the best in my time here. A club like ours shouldn’t be getting this far into cup competitions.
“We don’t pay our players, they play here for the camaraderie within the squad and because they can become better footballers.”