''We had about 10 days to prepare. I had to learn all the rules and everything. Tyran did a great job of teaching me and leading the team.
''Some of the skills come from indoor, but other than that it's a completely different game. Playing on the sand, you really have to adapt to that, and it takes time, but we did pretty well in the end.''
The contrast in the court surface is an obvious and significant difference between the two versions of the game.
''You can't jump as high and for an indoor player that's quite frustrating. It's all about timing and adapting to the wind, that's a big factor.
Gillespie used the same terminology as his team mate about the win - ''I'm stoked'' - but admitted he didn't really expect it.
''With Billy not really being a beach volleyball person, it was tough, but we got it done,'' he said.
''When he started off, his first game was real rusty, but he improved a lot and every game he was getting better and better. With a few more years and he'll be a gun.''
Gillespie said his knowledge of others at the tournament was a big help.
''All the good players in the tournament I've played against, so I knew how they played the game and I kind of had knowledge advantage over them. We had a game plan going into every game - and knew that if we both did our jobs we would be OK.''
Johnstone's role was to be a blocker at the net and to ''jump as high as he could".
''He's a big boy so he takes a lot of room up in the air and that makes the job a lot easier for me in the back court.''
Johnstone has been playing beach volleyball for five years, and has now turned his attention to the New Zealand title at the Mount on February 17-19 with an as yet undetermined teammate.
After that both players will focus on indoor volleyball and prepare for the New Zealand secondary schools championships in Palmerston North in late March.
Western Heights volleyball coach Eugene Bogun was at the Mount to see the win, and described it as an awesome achievement.
''I was always pretty hopeful they would do well because they are both talented athletes.
''Tyran's really experienced on the beach and has been playing on the tour over the summer and he's played over in America for New Zealand so there's a lot of experience there and Billy's just awesome at indoor and he transferred those skills to the beach.
''They worked well as a team and Tyran's leadership skills stood out and he led them through the tournament."
Bogun said the win was a good way to start the year and will give both players a lot of confidence for the indoor campaign.