The Warriors flanker made a welcome return from injury after three months out of action, scoring one of his side's four tries in a 26-5 success over Zebre at Scotstoun on Friday.
That success, coupled with defeats for Munster and Ulster Rugby, ensured Gregor Townsend's side rose back to the GUINNESS PRO12 summit.
And with the PRO12 beginning a two-week break, Fusaro insists Glasgow are comfortable at returning to their lofty position.
"It is great to be back at the top, the boys are really happy about it, especially going into the short break now," the 25-year-old told the club website.
"We have got a lot of time to build for Leinster in this position, that game away at the RDS is going to be absolutely massive. It will probably be one of the defining games of the season.
"We were really happy to get the first-half bonus point against Zebre. Obviously the second half wasn't as good, but it is great to get those tries and we are really happy.
"It has been a tough three months getting back from injuries, but I'm feeling nice and fresh now, so I am looking forward to the tail-end of the season."
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