It's not like his fights mean anything if he's holding back all of his power. What we have seen recently, however, is that he can casually eradicate foes that can contend with SSJB Goku and Vegeta. Sso the fact that Zamasu failed to do the same to the Saiyans--even being overpowered by Trunks/Vegeta--leads me to conclude that he's not on the same level as Beerus.
Originally posted by carver9
Beerus. We haven't seen an unleashed Beerus as of yet and he is treating everyone that he encounters minus Champa like fodder.
Whis said Goku and Vegeta could take on beerus together and win. Clearly they were less powerful back then and Zamasu just treated them both like fodder.