Both MiBr & 100T only played default Strats, so much default that they even played Killjoy on Ascent, an ancient comp.
My theory is that, speaking on the strategic layer, 100T won simply because Tejo abuse is better on Pearl
MIBR won the maps their default was good on, then lost the maps they might've made comp changes, since they looked uncomfortable in the comps they were playing.
Then, on the 5th map, both teams used their ancient defaults, but MiBr was uncomfortable with theirs, and 100T wasn't, why? Because although both cooked up different ACTUAL map comps, MiBr chose an ancient comp they didn't play properly that didn't have Tejo
While 100T just used the comp they were using last month
TLDR: Both teams saved strats, 100T won by Tejo abuse