Trailing by 17 at half-time, the Australian Conference winners staged a remarkable revival to pile on 24 unanswered points in the second period on the way to a second successive win over the Highlanders.
Bernard Foley was the chief destroyer, crossing twice either side of Israel Folau’s 10th of the season in a game-changing burst that began in the 54th minute.
The Waratahs had earlier appeared set for a quick exit from their first play-off appearance in three years when tries from Waisake Naholo and Rob Thompson, and a trio of Lima Sopoaga penalties, combined to put the Highlanders in a commanding position.
But the influence of fly-half Foley, who finished with 25 points, and some desperate defence late in the match, swung the contest in favour of the New South Wales franchise, who recorded their first post-season win since beating the Crusaders in the 2014 final.
Their hopes of more success now hinge on a semi-final date with either the Jaguares or the Lions, who meet later on Saturday.
No guts, no glory. Hello: semi-finals.
We keep the @Highlanders scoreless in the second 40 to keep our 2018 campaign on-track.
— NSW Waratahs (@NSWWaratahs) July 21, 2018
Watch the Heineken Champions Cup Final live on RugbyPass throughout Asia and Australia.