Their latest success takes them to fifth on the table and it was thoroughly deserved against a side packed with Wallabies who suffered the indignity of losing at home to the Sunwolves last weekend.
Remarkably, it is the first time the Blues have strung four wins together in the same season since 2011. They won a total of four last season.
"Some of our play was outstanding but then through our own errors we let them back into the game and they took their opportunities through their strengths – their kicking game and getting [Israel] Folau into the game," MacDonald said afterwards. "It's pretty hard to stop when they get that going."
Fullback Folau was a constant threat and his first-half score took him to 60 tries in Super Rugby; a competition record. The previous record holder was one Doug Howlett, a man familiar in these parts.
The Waratahs' Kiwi coach Daryl Gibson felt some decisions in the final moments could have gone either way but added the Blues are a different team this season.
"There's a lot more backbone to the Blues, no doubt," Gibson said. "To decide to run the clock down with three or four minutes to go; that's pretty gutsy. It shows definitely in their forwards – their willingness to compete at the ruck. There's starting to be a bit more steel in their team."
A suspended right wing Tanielu Tele'a? No problem, Caleb Clarke comes in for his first game of the season and scores a stunning try as his side pours on the pressure in the first quarter, suffer a bit of adversity later in the half when the visitors nearly come back on even terms, and then dominate the second half.
As usual, Rieko Ioane was again a constant threat with his pace and anticipation. Ma'a Nonu rolled back the years with an energetic performance at second-five which reaped him his first try of the season and his midfield partner TJ Faiane was again assured in his decision making and actions.
Apart from loose forward Blake Gibson's knee injury after seven minutes which forced him from the field, it appeared as if MacDonald was about to get his wish and see the Blues take control of the game in the first half.
Nonu featured in two assists for two tries – first with a cut-out pass for Tom Robinson in the left corner and then following a beautiful piece of deception to put Clarke under the posts.
With their big forwards breaking the advantage line with virtually every carry, and the Waratahs missing tackles and conceding ground, it seemed the Blues could do no wrong, but the second quarter put paid to that.
A series of penalties forced them into their own territory, with Folau soaring high, as he so often does, to haul in a Bernard Foley kick to crash over, and Will Miller scoring from a lineout drive.
The Blues' new patience was shown when Faiane scored after the break with a try after 14 phases which put his side on the front foot again but again came the Waratahs, this time through wing Alex Newsome.
Jake Gordon's try with five minutes remaining put the heat on again, but the Blues held firm. They will travel to Hamilton for a derby against the Chiefs with growing confidence.
Blues 32 (Tom Robinson, Caleb Clarke, TJ Faiane, Ma'a Nonu tries; Otere Black 2 pens, 3 cons)
Waratahs 29 (Israel Folau, Will Miller, Alex Newsome, Jake Gordon tries; Bernard Foley 3 cons, pen)
Halftime: 17-14
