The Australian has been one of the most impressive performers for the Wallabies in 2021 and is a constant threat with his sniping breaks from the base of rucks and scrums.
Weber said McDermott reminded him of himself when he first arrived on the Test scene.
"I liked to run everything. I've played against him once, for the Reds this year and he tore our Chiefs team apart that night so he's definitely a threat and something we've focused on because a lot of their game, particularly when they get quick ball and he's on the front foot, he can be pretty dangerous for those guys around the fringes," he said.
It was a job, among several, for him to keep an eye on.
But the start is the chance for Weber to consolidate himself in the side, something he appreciates, having played the first of his 10 Tests in 2015 but then having to wait until 2019 to play his second.
"It's incredibly satisfying to have a lot of that persistence and patience pay off. I'm under no illusions I'm a halfback playing in an era where we've got some of the greats, so I never take these opportunities for granted.
"I've had to fight tooth and nail to get back into this side over a few years. Ever since I made it back, it's been a goal to stay here and contribute as much as I can.
"Getting a start in a game like this has been one of those goals. Opportunities are few and far between with Aaron around.
"I've had one opportunity and I was real keen to play in a game as big as this against the Australians. This will be one of the biggest I've had to date," he said.
Each of the halfbacks was aware there were opportunities while Smith was away, and they were keen to make the most of them.
"I'm the first one that gets a crack and I'm pretty keen to stake my claim pretty strongly this weekend," he said.
"I don't need to go out there and try and be Aaron Smith. It is just about being Brad Weber and bringing what I can bring to the nine jersey and to help the team win."
He was confident in his combination with Beauden Barrett. While they hadn't played together a lot, as a combination, they had known each other since their high school days when involved in Hurricanes' schools.
"I've got no qualms in terms of a combination, or knowing where he's going to be. We've got a good relationship so I don't think we'll have any dramas in that department," he said.