George Watson's 5 - 10 Stewart's-Melville
For the second time in two days, the 4G pitch at Murrayfield came to the rescue of the competition's semi-final, after Myreside was declared unplayable for the second of the penultimate round matches.
Stewart's-Melville seemed to adapt better to the faster playing surface with more aggressive forward play and more incisive midfield running that nullified what was expected to be Watson's strong suits.
"I thought our commitment, particularly in the final quarter, was outstanding" said Stewart's-Melville joint coach, Bryn Lockie.
Fellow coach Chris Spence added: "We had more penetration in midfield and that was crucial. I was also delighted with the way we handled the set scrums and line-outs"
For Watson's, this was a second successive season of faltering at the semi-final stage of the Cup.
"We don't seem to be able to handle the big occasion games and that's something we have to look at" said Watson's coach, Andrew Ker. He added: " We didn't get going in the first 15 minutes and, for the first time this season, we were under pressure in the scrum. That limited what our back row could do. Their ten was a key player. He controlled the game."
Stewart's-Melville were much the more dynamic in the opening stages of the match and should have gone ahead had the pass to winger Leo Bargery not gone forward. But their first-half play was eventually rewarded with a penalty goal from stand-off Alex Hagart to give his side a 3-0 interval lead.
Watson's looked purposeful at the beginning of the second half and, from a clever midfield thrust from winger Dominic Johnson that set up a crucial ruck, the ball was moved on the blindside for full back Will Kelly to dive over for an unconverted try.
Stewart's-Melville quickly hit back with a storming run from Bargery and then quick transfer of the ball that allowed centre Jack Hannay to touch down under the posts leaving Hagart with a simple conversion kick and the final points in the match.
Scorers: George Watson's College - Try: Kelly. Stewart's-Melville College - Try: Hannay; Con: Hagart; Pen: Hagart.
George Watson's College: W Kelly; D Johnston, R Young, J Broadley, M Hunter; A McMillan, J Gray; M Johnston, A Ross, R Jack, D Marinello, A Middleton, I MacLennan, B Griffin, R Davies. Subs: M Horsman, R Hamilton.
Stewart's Melville College: M Black; L Bargery, J Hannay, D St Clair, A Greig; A Hagart, C Taylor; H Lindsay, C Halliday, R MacIntosh, A St Clair, J Morgan, M Campbell, J Duncan, R McPhail. Subs: J Johnstone.
Referee: D Shaw (Edinburgh University).