Easiest way to be sure would be to try find him versing you in his twitch archives, that's assuming he was streaming at the time.
I wouldn't think rank 7 is out of the question for Noxious however. He tends to play stupid decks a lot and doesn't take ranking up particularly seriously. But you can probably check roughly what rank he was using the archives to see it was rank 7 or close to it around the time you played this match.
Easiest way to be sure would be to try find him versing you in his twitch archives, that's assuming he was streaming at the time.
I wouldn't think rank 7 is out of the question for Noxious however. He tends to play stupid decks a lot and doesn't take ranking up particularly seriously. But you can probably check roughly what rank he was using the archives to see it was rank 7 or close to it around the time you played this match.