The pair meet in Christchurch on Saturday after the Drua sealed a seventh place finish, their best performance since joining Super Rugby last year, to leave Byrne praising the progress made by his players.
"It's definitely one of the highlights, if not the highlight (of my coaching career)," said Byrne, who played Australian rules football before moving into rugby union as a highly-rated skills coach.
"I've been fortunate enough to be involved in very experienced teams with legendary players, and they challenge you to be a better coach.
"With these guys here, they've come from such a low base and they work so hard to get there. It's massively satisfying when you sit back and see how much work these guys do to get there.
"That's the highlight. Where we 18 months ago, to where we are today is a massive highlight."
The Drua were one of two teams, alongside Moana Pasifika, to join the expanded Super Rugby competition in 2022, with the Fijians finishing 11th in their first year with only two wins from 14 games.
Byrne's team showed a marked improvement in 2023, however, winning six times to book their spot in the next phase of the competition.
"Our expectations internally have been as strong as anyone else's," said Byrne.
"In a 12-team competition if you believe you've got a reasonable team you've got to go after that eighth position.
"That wasn't an unrealistic expectation for finals. We knew we'd do it."
The win over the Reds was especially emotional for Byrne, who had made a short trip to Australia during the week to spend time with his father before he passed away on Friday.
"These boys just got around you when I got back," he said. "I left my family in Australia and I came back to my family in Fiji.
"I was able to spend some quality time and I'll be forever indebted."
