The key is definitely Taylor's jab.

Mendoza didn't use the jab at all against Lacy and still managed to land huge shots against Lacy's crap defense. If Taylor can follow his jab with big right hands, Lacy is going to get KO'd.

OTOH, if Taylor tries to bang with Lacy instead of using his superior boxing skills, he will be taking a huge risk. Brawling isn't JT's style, and even worse, it's the only way Lacy can win.