The Blues' 23-8, four tries to one, victory ended a 15-match unbeaten streak from the Chiefs against their northern neighbours dating back to 2011. It has also breathed life back into the Auckland outfit's faltering season after they had lost their previous four to slip all but out of the playoff race.
It did not look promising when the Blues bumbled their way through the opening quarter to trail 5-0, but eventually they worked into a 10-8 halftime lead and closed the deal well with two crucial second-half tries to forwards Ofa Tu'ungafasi and Gerard Cowley-Tuioti.
"It showed signs of a little bit of last week, especially in those first 20-oddd minutes but we kept at it and kept at it and got there in the end," said MacDonald in reference to last week's 22-12 defeat to the Hurricanes that the Blues dominated for long periods.
"Everyone was starting to get a bit anxious, including us in the box, because we were making the same mistakes as we have done. We've put a lot of work into that area of the game. It just wasn't quite happening for us, but we persevered.
"In this competition it's how you respond to the setbacks. Last week we didn't respond well; this time around we scampered back and defended our line and got away without giving away a try and all of a sudden it was our turn again.
"Even though we weren't perfect, the effort in terms of the scramble D and recovery was fantastic.
"We scrambled well and when it was their turn to attack we really held them still and didn't give away too many basic penalties. We grew in confidence, and with that confidence we got excited about getting ball in our hands again and made the most of it."
MacDonald was especially rapt to see his forwards' effort – both starting props went the full 80 – rewarded with that bonus-point drive at the end off the lineout drive.
"It was good reward. We were underneath our posts with a scrum and 2-3 minutes to go. Then [it was] penalty, maul, penalty kick to corner, try. The forwards took over that last three minutes and owned it.
"For two props to play 80 minutes and be able to do that was pretty impressive."
MacDonald was trying not to look too far ahead after such a hard-fought victory, even though everyone was well aware the Crusaders were next up in Christchurch, and the situation remained just as desperate. He said they would enjoy the chance to belt out their victory song for "the first time in a while" before switching thoughts to the next opponent.
If you want to be a serious contender in this competition you're going to have to work really hard for 80 minutes every week. That's been our mindset, we've trained really hard and every week you feel it's not far away. So to see a performance like that feels good because you know it's in this team."
On Tu'ungafasi's try being a tad fortunate, with the big prop appearing to drop the ball into a Chiefs player in his scoring movement, MacDonald said: "We've had a few go the other way, so I'm not complaining. We earned our tries and I thought we created a lot through our attack. It was good reward for Ofa."
Chiefs coach Colin Cooper didn't quite see it that way, as puzzled that Tu'ungafasi's try was awarded as he was that his own forward Pita Gus Sowakula's 71st-minute one wasn't.
"At 10-8 we were in the fight," said Cooper. "Tries went their way which maybe should have been looked at and weren't, and we get awarded a try and unless the TMO got other views, I couldn't understand why Pita Gus' [effort] wasn't a try.
"We didn't get the rub of the green."
Asked to clarify, Cooper said Tu'ungafasi had "clearly knocked on" and Sowakula told him after the game he had regathered the ball before he grounded it and was puzzled why his try wasn't awarded.