It’s extremely easy to see a “Cobra Kai”-style dynamic between Rupert and Cartrick, especially since the former has already used similar evil mentor tactics on Nate (Nick Mohammed), and seems to generally thrive on borderline supervillainy, billowing black coat and all. However, while Cartrick’s appearances in the show so far have depicted him as an unpleasant and bitter man with a host of personal issues, he’s still a highly qualified, professional top-level soccer coach. Rupert attempts to get Cartrick to intentionally hurt Jamie. The coach refuses (and uses profanity) to do so. The crowd then turns against Rupert and he is forced to leave the venue and show while being abused by the audience.
The “Ted Lasso’ show isn’t the most realistic, but Rupert failing to “sweep” the leg is an outcome that is quite believable. It’s impossible for a coach to order players to hurt people after the owner of his team, a Darth Vader-like figure, storms up and gives them orders. Even a coach who is far less moral than Cartrick would understand how those images could destroy his credibility.