I think the key word is respect. If you come in and get it, then keep it the players respect you'll have them pulling up trees. The players knew that Zidane wouldn't accept less than 100%. Same with SAF, same with the old Jose, same with Wenger.
As soon as the players get a whiff that you're sinking, or you don't have the power or balls to bomb them out then its all over.
If United back OGS then he needs to make a few statements by binning off those who are not pulling their weight. Pogba, Sanchez and Lukaku need to go first. I'd rather have players like Young, Smalling and Jones who give the effort but lack the quality than the other way round (get rid of those players in wave 2...)