I think Rivera was on the verge of falling apart. He was afraid to throw strikes.
He does that from time to time but all it took was 1 pitch. I would have at least given Saul 1 chance to get the #8 hitter out to get out of the inning unscathed. Joel is the last guy I want in the game in a crucial situation with runners on base, especially when he wusses out and throws his slider instead of his 96 MPH fastball.