He may have won Super Rugby titles with the Crusaders in his playing career but was like his players and feeling some nerves ahead of the game. That was a good thing because it was the playoffs, and that was what you expected.
"You have got to be confident in the work we have done to date. You've got to trust what you've done and put you in this position. It has served us well all year and we can't forget that, and it is no different for me as well," he said.
They were well aware of the approach the Highlanders would bring to the game.
The only people writing them off were the media, he said.
"We've played them twice, and they've been two hard games, really hard, games. They've been right in it until the final plays of the games. We're under no illusions, they've got nothing to lose, and they're dangerous when they are in that space.
"We grabbed the key moments in those games and we've got to make sure we can grab them this week as well," he said.
"We've got nothing to lose as well, it's do-or-die for both of us."
MacDonald said in preparation for the playoffs and looking back at clips of their play earlier in the season, it was apparent the Blues had come a long way.
"We've moved a lot of areas forward, and that is what you would hope. And looking at some of the older clips of the Highlanders, they have improved a lot as well.
"It's about getting it right at the right time. That's what finals rugby is about," he said.
In hindsight, he felt the month at the start of the season in Queenstown had turned out to be helpful for the side. All teams had to cope with Covid and sickness. It was something you could grizzle about or deal with, and that was what he felt the Blues had done well.
The Highlanders were a side who thrived on the fast ball they could get through their pack. Both of their halfbacks, Aaron Smith and Folau Fakatava, were dangerous.
"They've got enough firepower, they've got dinky kicks, and they've got clever ball carriers who can offload. They're always well organised in the maul.
"They took us on in the maul here last year in the final and got a little bit of success and in the past they've banked on their scrum as well," he said.
"They're a good rugby team. They'll feel like they've under-performed to their potential and this is an opportunity for them to show everybody how good they are and we're wary of that," he said.
The two halfbacks offered different threats. All Black Aaron Smith's pass was quick and long.
"He can clear a lot of defenders quickly and all of a sudden there's space and Fakatava's running around the base is as good as anyone in the world. He's dangerous, he's quick and he seems to make good decisions and very rarely gets isolated. He brings confidence when he's on the grass, he lifts the game up and brings another dimension," he said.
No matter what might happen in the remainder of the competition, MacDonald said last weekend's win over the Waratahs was probably one of his prouder moments in coaching.
"The guys we put out there, they didn't go out there and hope they could win. There was genuine belief. That shows us we're really growing some depth, and that is important. This competition has been about that, and it has held us in good stead.
"But there's a lot of players that we're going to see in the Blues for the next 10 years where that was their launch pad for their careers and they finally realise that they belong at this level, and they can do it," he said.