Throughout the course of his run include Jack of Hearts, Morg & Terrax to the list. Also include Thanos as he had to leave or he would've died by his own words. That tells you how powerful Tyrant was for him to say that. Plus throw in getting the better of Galactus and your point is ever better :-)
I think the team maybe wins a majority but lets remember many of that team gets dealt with rather quickly in one shot or a few.. I'm talking about WW, BA, Despero, Zoom, Lobo to name some off the top of my head. So, it's not like he'll be facing the whole team all the time. The team will shrink and tyrant's chances thus increase.
Tyrant wins. His full power was clearly implied when Galactus chose to retreat. Galactus mentioned that there would not be much to rule over after a fight meaning Tyrant (and Galactus)would be throwing around energy that would be destroying solar systems and possibly the entire galaxy (depending on what he meant makes a big difference but no way did he mean the Universe).
With Thanos Tyrants first few shots were at levels designed to beat the other superheros. He upped a level on his last energy burst and Thanos left. If he was in a position to give Galactus a good fight then he is capable of going much higher. That is why Thanos said tyrant WOULD eventually kill him.
If Tyrant absorbed all his energy kickball things he'd probably be very close to Galactus.
I missed the story where tyrant died though.