NSW Waratahs may need to create history if they are to win their second and Australia's fifth Super Rugby title.
The Tahs became Australia's first semi-finalist since 2015 when they sensationally recovered from a 23-6 halftime deficit to beat the Highlanders 30-23 in Sydney on Saturday.
Skipper and five-eighth Bernard Foley contributed all but five of the Tahs points, notching two tries and six shots at goal.
Three hours after completing their remarkable win, NSW learned they would have to travel to Johannesburg on Sunday morning to face South Afican conference winners the Lions at Ellis Park in Johannesburg on Saturday.
Unless the defending champion Crusaders lose at home to New Zealand rivals the Hurricanes in the other semi-final, the Tahs face a task that has never been achieved in the 21 previous seasons of the competition - win successive finals matches overseas.
If they can find a way past the Lions, who thumped them 29-0 in Sydney in May, the Tahs could yet host the final if the Hurricanes upset the Crusaders in their Saturday clash in Christchurch.
The Canes have won eight of their past 12 against the eight-times champions and split their two regular season games this year, with each team victorious at home.
The Crusaders, who comfortably topped the overall ladder on their way to winning the New Zealand conference, scored a 13th-straight victory with a 40-10 home conquest of the Sharks on Saturday.
Wallabies backrower Peter Samu was among the Crusaders' five try scorers, as they pulled away in the second half.
South African teams have lost all 13 of their finals games in New Zealand.
Two tries to halfback TJ Perenara, helped the Hurricanes to a 32-31 success in an all-New Zealand quarter-final against the Chiefs in Wellington on Friday.
The visitors scored two late tries after trailing 32-17.
Hurricanes winger Ben Lam crossed for the 15th time this season, joining Waratahs winger Taqele Naiyaravoro as the 2018 competition's leading try scorer.
The Lions overcame a second half fightback by first-time finalists the Jaguares to score a 40-23 win over the Argentine team .
While they trailed 6-0 early on, the Lions scored 24 unanswered points and lifted again after the Jaguares slashed the gap to four points early in the second half.
That win secured them a home games against NSW, whose costly last-round loss to the Brumbies enabled the Lions to move above them into second on the overall ladder.