The Celtics have consistently held Giannis in check. His TS% as a whole in that span is 62% so the celtics have held him more than 10 points below his average. Even with the losses of Grant Williams and Rob Williams, the Celtics held him to 21 points on 20 shots tonight.
Celtics and Heat have his number. If Bucks got moved to the West, Giannis might go to the finals every year (just to lose to the Celtics or Heat).