Four Easels, Five Canvases

Five canvases numbered 1 through 5 sit stacked in random order, face down, and four easels stand in a row. You reveal canvases one at a time; each revealed canvas must immediately be placed on a still-empty easel of your choice and can never be moved again. The game ends the instant all four easels are occupied — the fifth canvas is never seen. You win if the easels read in strictly increasing order left to right. Playing optimally, what is your probability of winning?