Cummings claimed his 12th Cup victory after Viewed hit the front halfway down the straight, doing just enough to hold off a dogged finish from British stayer Bauer.
New Zealand-bred four-year-old C'est La Guerre plugged into third, while never looking likely to catch the first two.
Alessandro Volta, Septimus and Honolulu set a torrid pace to the turn, when the Auckland trained Boundless briefly too over.
Best-backed New Zealander Nom du Jeu settled midfield and just battled in the straight.