Gilroy was on the scoresheet in Limerick when Ulster upset the odds against the competition's top seeds but he can also claim to be the first player to have crossed the whitewash at the new home of Irish Rugby.
The 22-year-old scored the opening try in front of a huge crowd at the Aviva back in the summer of 2010 as Ulster and Leinster U20s faced their Munster and Connacht counterparts in the first game to be played at the stadium.
Memories of that particular day in Dublin and of the euphoric scenes at Thomond will be fresh in Gilroy's mind when he heads back to the Irish capital and he is keen to create a similar slice of history this time around.
"I think was eight years old when Ulster won the Heineken Cup back in 1999 so to be scoring a try against Munster in the quarter-finals was just like a dream," said Gilroy.
"I'd definitely say it was the biggest win of my career so far. It was euphoric, especially because it was a Heineken Cup quarter-final playing Munster down at Thomond Park in their own backyard. To beat them was just something else.
"I can remember playing at the Aviva for Ulster and Leinster U20s against Munster and Connacht U20s in an exhibition match. That was the first game at the stadium in June 2010 so it was pretty packed.
"It was a special occasion and a great day. I was lucky to get in for the first score at the ground thanks to a nice kick from Paddy Jackson so, like the win at Munster, it was another very memorable day for me.
"Personally, I love playing in front of big crowds, entertaining the crowd and getting them on your side. The atmosphere brings extra excitement to the game and spurs me on.
"It will be hard to beat the atmosphere that we had at Thomond but I can imagine that the atmosphere for a semi-final at the Aviva will be a couple of gears above that, which will be difficult to believe!"
Gilroy's sublime solo score against Munster earlier this month set the platform for Ulster's quarter-final win but he has been quick to deflect the praise, instead piling it on senior figures such as Heineken Man of the Match Stephen Ferris.
Ferris fought off an ankle injury that threatened to rule him out of action in the days leading up to kick off and Gilroy admits that a similarly impressive individual display from the star blindside this Saturday would go a long way to guiding Ulster to a second Heineken Cup Final.
"We've got some world-class players in our in team, with the likes of Johann Muller, Ruan Pienaar, Rory Best and Stephen Ferris and everyone knows good a player Stephen is," added Gilroy.
"For him to be a doubt to play against Munster but then to perform how he did was such a huge lift for the whole team.
"That definitely inspires you. You watch guys like Stephen when you're growing up and then next thing you know you're on the pitch alongside them. They're a huge inspiration. You take great energy from what they do and use that to your advantage.
"Last year we were put out in the quarters against Northampton and we're a bit sick of being second best with the other Irish provinces finishing above us so we really want to move on now."