After turning round 34-0 down, Van der Merwe's efforts, plus a try apiece by Niko Matawalu and Jonny Gray, helped Glasgow salvage one of the most improbable try bonus points in Heineken Cup history. But there is only so much delight you can feel when you end up on the wrong end of a 51-28 scoreline.
Which is to say, not much delight at all. "I guess it is okay to score a few tries but it is not the result we wanted," said Van der Merwe drily.
"But yeah, it showed what we can do," the 27-year-old continued. "I think we let them play a bit too much in the first half. We got a bollocking in the changing room but we stepped up in the second half.
"We don't know if Toulon maybe gave up a bit with their lead. We are happy with the second half but they got other tries in too. We pride ourselves on our defence. We have to do better next week."
A combination of factors - chiefly a late return from international duty followed by a bout of sickness - has limited Van der Merwe to just one start in six competitive games this season. Brought off the bench at the start of the second half in the Stade Felix Mayol, in a tactical adjustment that also saw Matawalu move to scrum-half in place of Henry Pyrgos, the prolific winger showed he had lost none of his sharpness when he claimed his first touchdown after just two minutes.
"At half-time the chat was about showing who we are and what we pride ourselves on," Van der Merwe explained. "Once we got the first try, and then the second try, the guys out on the field were saying let us push for that bonus point as it is going to be important.
"It is massive for us. Any point away from home is a bonus for us and we got it against the defending Heineken Cup champions. Wow. We will know at the end of the group stages how important that point is."
The Heineken Cup format means Glasgow will conclude the pool stage of the tournament by hosting Toulon at Scotstoun. In light of their second-half performance on Sunday, the thirst for revenge among Gregor Townsend's players was almost palpable. Van der Merwe's view of the return fixture echoed that of most of his teammates.
"They have the 16th man here," said Van der Merwe of the intimidating atmosphere created by the Toulon crowd. "We could hardly call plays on the sideline. On the bench you could not hear each other. Hopefully the Warrior Nation will step it up and fill out Scotstoun and pay them back with a win."
With intense competition for wide places in the Glasgow side at the moment, Van der Merwe seemed to hint that he was miffed to be left out of the starting XV on Sunday. In part, that was a knock-on effect of Townsend's choice of Pyrgos at scrum-half, largely because they wanted his goal-kicking abilities in the side, but after their second-half display it is reasonable to expect that Glasgow will form up along more conventional lines against Exeter Chiefs next Sunday.
Josh Strauss, the Glasgow No.8 suggested a valuable lesson had been learned against Toulon and that Glasgow will take a very different approach against the English side.
"We were pumped in the first half because we had come over wanting to make a statement," said Strauss. "I don't know if we had played the game too much in our heads in the week. Maybe we gave them too much respect, the Heineken Cup is a massive deal and maybe we put too much emphasis on it.
"We just got overexcited, had people going out of our structures, people trying to make plays and it did not work for us. We are a good team when we stick to what we do well and we did not do that. It is a big lesson for us.
"It's the first game of the Heineken Cup, so it's better now than later. We can learn something from it and come back next week better and stronger. We have to remember what we did well in the first five [RaboDirect PRO12] games and stick to that next week."