The Crusaders took an early lead through a Dan Carter penalty but the Waratahs took control thanks to a brace of tries from young winger Lachlan Turner, both converted by Kurtley Beale, which gave them a 12-3 advantage.
Carter cut the deficit with another fine penalty before number eight Mose Tuiali'i touched down in the corner on the stroke of half-time, with the Waratahs in front 12-11.
Fly-half Carter kicked the Crusaders in front soon after the restart before a Wyatt Crockett try was ruled out for an off-the-ball infringement.
However, Carter sealed the win with a drop goal and yet another penalty five minutes before the end to seal the triumph.
Crusaders captain Richie McCaw told Sky Sports: "The defence were outstanding. You've got to dig deep when you're down and we did. We wouldn't be defeated.
"Although we were behind, we felt we were on top at half-time. We knew if we could keep our composure at the start of the second half, the points would come."



