Ireland stunned hosts South Africa with a deserved 24-14 victory in their Rugby World Cup Sevens quarterfinal on Saturday, setting up a meeting with holders New Zealand.
Fiji will take on Australia in the other semifinal.
Jordan Conroy scored as brace of tries for the Irish, who were worthy winners as they disrupted the South African set piece and forced the home team into uncharacteristic errors.
"It’s insane," Ireland captain Billy Dardis told reporters. "To beat South Africa in a World Cup quarterfinal on their own patch, it doesn’t get much bigger.
"We weathered their purple patch in the first half. We wanted to come out here and kill the party. It is some atmosphere and they would have lived off that if they had got some momentum.
"We haven’t beaten New Zealand in the world series. We have been close a few times in the last couple of years, this would be a good time to do it."
Tries by Scott Curry and Moses Leo saw New Zealand come from behind to defeat Argentina 12-5 in their quarterfinal, while Henry Paterson and Maurice Longbottom crossed for Australia in a 14-5 win over France.
Samoa took an early lead against Pacific rivals Fiji but the quality of the latter shone through as they scored three tries in a comprehensive 21-10 win.
New Zealand are seeking a third successive title after beating England in the last two finals that were played in Moscow in 2013 and San Francisco four years ago.
The semifinal line-up in the women’s competition will feature holders New Zealand against France, while Australia take on the United States.
The finals of both competitions will be played on Sunday.