It was an interpro that will live long in the memory, but for victorious Leinster head coach Leo Cullen, relief was the overriding emotion.
Ulster's only previous away quarter-final victory in the competition came seven years ago at Thomond Park and they came agonisingly close to a greater upset against the defending champions in their own backyard.
Dan McFarland's side paid little heed to the script and Kieran Treadwell's early try set the tone at a colourful and boisterous Aviva Stadium.
The visitors fell behind for the first time in the 53rd minute, but Luke Marshall's try 10 minutes later had the large hordes of Ulster supporters in the stadium dreaming of victory with the sides level at 18-18.
Only one more score would following in a gripping final, with Ross Byrne ignoring his obvious physical discomfort to coolly split the posts as the holders joined Munster in the last four where they await the winners of Racing 92 and Toulouse.
After overwhelming Wasps, Bath and Toulouse in the pool stages, this was simply all about the win.
The Six Nations disruption was referenced post-match and the lack of time on the pitch for his front liners appeared to be an issue early on before they dug deep to edge out their rivals.
"We are relieved to be through to the semi-final," Cullen told RTÉ Sport. "I don't think we were anywhere near our best.
"I was frustrated that we didn't give a full account of ourselves. I thought the players showed good composure when it was 18-18 and the game was in the balance.
"It was real cup rugby in the last 10, 15 minutes. It was pleasing the way we stuck at it and I thought we looked in reasonable control in the last five minutes where we held possession well.
"You don't want to be too clever at that stage. It's about getting through."
Some observers have suggested that last year's double winners have not shown the clinical form they displayed throughout last year's decorated campaign, but aside from the serious injury suffered by Dan Leavy, they look in rude health.
Eighteen points clear of Ulster at the top of Pool B in the Pro 14, they are looking good at the business end of the season in Europe, where a final date with Munster remains a possibility.
Cullen is adamant that improvement is required if they are to sign off with silverware.
"We know we are in two semi-finals, but it's about how do we build cohesion and our levels of performance so that when it comes to those games, we give a better account of ourselves than we did today.
"Some of that was down to Ulster, but some of it was in our own control as well."
The head coach also had special praise for match-winner Ross Byrne with his 71st minute penalty the difference between the sides on the scoreboard.
After missing his first two kicks of the day, the out-half exuded confidence after hobbled away from the kicking tee after the winning penalty to be replaced by Rob Kearney.
"He was cramping up and we were happy if he went to the corner, but he took it on himself to take the shot at goal," Cullen revealed afterwards. "I thought he might have gone to the corner but he showed some good character.
"He was struggling, even after the kick. I thought Ross did well under difficult circumstances."
