It will take a long time to drain Sentry, since he has the power of a million exploding suns. By the time time he realizes this, Triumph will be eaten by the Sentry's thought manifestation, the Void, or Sentry will simply beat the holy hell out of him. Something Superman could not since he was being drained and stores solar energy in his cells where the Sentry has the power of a million Exploding Suns and can still fight on even if being drained.. He says so himself.
Superman helpless:
Sentry saying he has the power of a million exploding suns...
Sentry wins. Cause whenever their's Sentry, there is the Void.
Sentry is a double edged blade. 😛
Other than that quote, you actually gonna prove that Sentry literally has the power of a million exploding suns? It's quite possibly an overexaggeration. (not saying he's not powerful, but Silver Surfer has stated he can do 'anything' before. Anything>a million exploding suns, so...) Sentry's good, but I haven't seen anything to suggest that much power. The Void gives a scope of his powers, and though it is impressive, it doesn't really equate to "a million suns".
Triumph's not too shabby either... I'm giving it to him. Though not by a whole lot.