I think in terms of execution and Xs and Os that GS will be fine. They can adjust and shoot the ball better. They still had a very good defensive effort and Cleveland clearly has problems scoring in the halfcourt on them when the game bogs down.
You just really don't know about the intangibles though. This is a new team on this stage and they haven't really had any adversity all year, on the road on that stage guys could easily get tight and not play up to their potential. It should be a madhouse in Cleveland.
I still say they will be OK and pull it out. Don't think LeBron can carry that much of a load without sacrificing efficiency for 3 more games, his passing right now is on a next level like he has a cheat code but his jumper has struggled throughout the playoffs.