Well, if I recall things correctly, his commandment is 9th among the 10. So if his power is in proportion to that...
Well, he may be arrogant during the day, but I'm sure he was okay during the day time so long as no one tried to fight him. And his power grows a lot until he peaks at noon... so considering he obliterated the vampire king who was somewhere north of 4,800 in power level while only barely peaking, then it wouldn't surprise me if Escanor could fight one of the TCs on relatively equal footing.