The Waratahs, the defending Super rugby champions, have still not found their best form this year but are growing in confidence the longer the season goes.
Michael Hooper, Adam Ashley-Cooper and Rob Horne all scored tries for the Waratahs on a wet and windy night in Sydney.
The Rebels were always behind but gave themselves a chance of snatching victory at the death when replacement Bryce Hegarty finished off a long-range try in the corner.
Jack Debreczeni, who had kicked three earlier penalties, landed the sideline conversion but time ran out for the visitors as the Waratahs held on over the final five minutes.
The win lifted the Waratahs into sixth place in the standings, in position for a playoff wildcard, but they can take top spot in the Australian conference if they beat the Brumbies next week.
The Waratahs recalled three forwards, Mitchell Chapman, Tatafu Polota-Nau and Jacques Potgieter and were rewarded with an early try to Hooper off the back of a rolling maul.
Ashley-Cooper crossed in the 20th minute to give NSW a 13-0 lead after Bernard Foley had booted an early penalty but Foley then missed some easy shots at goal.
The Rebels got on the scoreboard with a booming penalty from Debreczeni near the halfway line then cut the margin to four points with two more penalties after the break.
Horne scored out wide to restore the Waratahs' advantage before the Rebels launched one last raid which got them to within two.
The Crusaders made a flying start in Christchurch before being reeled back in, but had enough to pull away again in the second half. They were quick off the mark and were ahead two minutes in, Mitchell Drummond crossing after a break from Nemani Nadolo.
Colin Slade added the extras for a 7-0 lead.
They continued to pour forward and added a second try 16 minutes in. Nadolo was the creator again, stepping in and out of tackles and putting up the final pass to Jordan Taufau who did the rest, with Slade again on the money with the extras.
Dan Bowden got the Blues going with a penalty, and they got further back into it nine minutes before the break with Francis Saili slipping Dan Carter's tackle and dotting down, with Bowden converting to 14-10.
The Crusaders would score the final points of the half, though, with Slade splitting the posts with a late penalty.
They continued where they left off in the second half, Tom Taylor breaking clear to score a third try and Slade converting, and a bonus-point score arrived on the hour-mark as Codie Taylor went in after good set-up play from Carter.
The Blues rallied through an unconverted 63rd-minute Brendon O'Connor try but there would be no grand comeback.