Koch earned his 50th Test cap, while Van der Merwe was one of four players to make their Springbok debuts, and to crown things off for Van der Merwe he scored his first Test try and earned the man-of-the-match award.
Koch, who started the match in a Rugby World Cup-winning front row with fellow prop Ox Nche and hooker Malcolm Marx, said the win made the occasion even more extraordinary.
“It was very special playing my 50th Test,” said Koch. “It was a dream come true, and the boys were unbelievable.
“I’m very proud of the team. They showed real character in the second half to get the win.”
The experienced prop added: “Winning my 50th game was amazing. These opportunities don’t come along every day, so I’m very proud.”
The occasion of running out in the green and gold for first time was equally memorable for Van der Merwe, who said: "It was an incredible experience to play my first Test and it was very humbling to earn the man-of-the-match award.
“The way we prepared in the last two weeks gave me a lot of confidence in the systems, and it allowed me to just be myself.”
While such an occasion could come with a fair bit of nerves for most players, Van der Merwe said the experienced players around him kept him at ease since Springbok coach Rassie Erasmus announcement the matchday squad on Tuesday.
“There was no real nervousness, so I could just be Edwill,” said the speedster. “The guys around me like Jesse (Kriel) and Makazole (Mapimpi) gave me a lot of confidence by always chatting to me, which made my job easier.”
Capping off the occasion, he was also one of the try-scorers as the Boks scored four tries and were awarded a penalty try – and it was clearly a moment he will never forget.
“I called Grant (Williams) for a ball off his shoulder, and I couldn’t believe it when I went through and crossed the tryline,” said Van der Merwe. “I was overcome with emotion and took a moment to take it all in because it was very special.”
The Boks will depart for South Africa on Sunday night with a massive challenge lying ahead of a Test series against Ireland and then a historic match against Portugal in the Castle Lager Incoming Series, and Koch said this victory gave them confidence and allowed them to build momentum going into the back-to-back Tests against the world’s second ranked team, Ireland.
“Our performance wasn’t perfect, but we showed glimpses of good things that we can build on,” said Koch. “The young guys that put up their hands was also a good sign for South African rugby, so we are really looking forward to Tests against Ireland and Portugal.”