Trailing by 17 at half-time, the Australian Conference winner 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 a 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 five-eighth 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, which recorded its first post-season win since beating the Crusaders in the 2014 final.

Hopes of more success now hinge on a semi-final date with the Lions, which beat the Jaguares in their play-off match.