Gideon's Triumph

A creature that attacked and was removed from combat (such as by Spires of Orazca) still attacked, so it can be sacrificed.

Gideon’s Triumph can be cast after combat damage has been dealt. In this case, the target player chooses one or two creatures that attacked or blocked this turn and have survived combat damage.

Gideon’s Triumph can be cast before combat damage has been dealt. In this case, it can be cast before or after blockers have been chosen.