The Lions are through to their third straight Super Rugby final after powering over the top of the NSW Waratahs 44-26 in Johannesburg.
The South African team recovered from a slow start in their semi-final to earn another shot at the Crusaders after going down to the New Zealand powerhouse in last year's decider.
Things didn't go to script early for the Lions on Saturday as the Waratahs defied their underdog status to snatch a 14-0 lead after just 10 minutes on the back of 80 per cent possession to silence the home crowd.
But the team that belted the Waratahs 29-0 in Sydney back in April was never going to simply fold and hand them their first ticket to a final since 2014.
While the game was there to be won for the Waratahs, as a Tom Robertson try just before the break made it 19-19 halftime, the Lions grinded down the visitors by continually getting into threatening attacking positions.
After a tense opening 15 minutes to the second half, flyhalf Elton Jantjies slotted a penalty goal to put the Lions in front to start a matchwinning 10-minute period.
Substitute Damien Fitzpatrick hardly had time to gather composure once he was on the field for the Waratahs before he was sinbinned and the Lions capitalised almost immediately.
Hooker Malcolm Marx crossed for his second try of the match in the 58th minute before Kwagga Smith, who was the best player on the field, ensured he also had a double shortly after to give the Lions a 15-point advantage.
Waratahs substitute Jake Gordon scored a consolation try, which captain Bernard Foley converted with five minutes to go, but even that was cancelled out from Courtnall Skosan getting on the end of a terrific kick just before fulltime.
The last remaining Australian team were hot early on the back of barnstorming tries from Ned Hanigan and Israel Folau before the Lions hit top gear after 20 minutes.
"I think we've come along a long way this year, for a young forward pack and a couple of first-timers in Super Rugby and they're going to be a hell of a lot better having this experience," Foley said.
"I think we can take a lot from this, we're only disappointed we're not still alive in this competition and playing for the cup next week."
The Lions will now make the trip to Christchurch searching for their first title when they play the Crusaders in the final on August 4.
"I think overall it was a decent performance but we'll probably have to be 50 per cent better next week, there's a lot to work on," Lions captain Warren Whiteley said.
"We just tried to get a bit more direct (after the slow start) we always try to turn to that but the guys stepped up. The Tahs put us under pressure, I thought they were right in the game until the end."
