With Giannis, given that the refs allow him to do what he does, you have to prevent him from getting his shoulder past you so he can just finish at the rim, and then there is one critical moment where he makes some other move, often a spin or the launch of a fallaway.
Jaylen did his job. Giannis didn't beat him. But if you want to stop him, you need some help to dig at the ball at exactly the right moment. At the end of the game we just gave him too long once he had slammed his way into the lane, and he got the shots he wanted and made them.
It is a good strategy during the game to not predictably double Giannis and allow the Connaughton or Allen or Matthews to get going shooting threes. But in the last two minutes, role players don't want to take those shots. We need to do something other than let Giannis get someone out on an island where no one can stop him.