Rong Bo and Feng Man had a deep understanding of the strength of an Eminent Celestial since they were both Eminent Celestials as well. If both of them joined forces, there was no doubt they would be able to defeat an Eminent Celestial. Naturally, there were exceptions to this. If their opponent mastered a Divine Ability from a Devata Realm or possessed a Celestial Supreme Treasure, let alone two of them, even if they had another two Eminent Celestials helping them, they still would not be a match for their opponent.
An Eminent Celestial with a Celestial Supreme Treasure had strength comparable to a Three Tribulation Bodiless Celestial. If the Celestial Supreme Treasure was of a higher grade, the strength it granted could be even stronger than a Three Tribulation Bodiless Celestial.