A hand injury earlier in the season prevented van der Merwe from reaching his target of 100 appearances in a Glasgow shirt in his sixth season at the club.
However he was able to mark his return in style, coming off the bench to finish off Finn Russell's looping pass with aplomb, and snatch a semi-final victory against Ulster in a classic encounter at Scotstoun.
And after Russell gave the Canadian international the plaudits after the game, van der Merwe returned the favour and toasted the fly-half's ice cool match-winning conversion.
"I didn't even look at it," he said. "I couldn't look. I looked at the grass, looked at the ground, and just listened for the crowd. I don't like those kind of things.
"But I'm so glad he made that kick. He's a young guy, with all that pressure on his head. It just shows the quality of this team.
"The message I had to bring on when I came off the bench was for the guys just to keep enjoying it. For a lot of them it was their last game in Glasgow, at Scotstoun, so they had to keep enjoying it.
"But we're actually at the final and I'm just so thankful. I'm thankful to the team, because everyone played so well and now it's our chance.
"A few weeks ago my scan [on the hand] wasn't great, but after that my strength started getting better and I'm so glad that I could play a part in this game. I couldn't leave this amazing city and those amazing supporters without signing off.
"From the start of this year, our goal has been to be the first Scottish team to win this title. You can't be shy about it; you have to believe it.
"Like our slogan says: Whatever it takes. That will happen this week."
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