Self-teaching 1st year PhD Microeconomic Theory How should one proceed if he wanted to master the microecon theory course typically taught in the 1st year of a PhD program on his own? Which text(s) and/or online course(s) should he follow? Suppose the guy has had a good training of econ up to the intermediate level and is familiar to the math topics the microecon course would typically demand.

Thanks in advance.
My prof is always telling us, if we want to pursue PhD level Econ in the future, we should master the full content of the following book:

Microeconomic Theory. Andreu Mas—Colell Michael D. Whinston and. Jerry R. Green. New York Oxford OXFORD UNIVERSITY PRESS 1995.

He also mentioned that there's main difference in viewpoint between graduate-level and top-level PhD Microeconomics. While in Grad School students calculate and theorize in the vector space, PhD students do mathematical operations using set theory almost all the time.