The Leinster forward, leading his country for the second time, feels the commitment shown by newcomers such as Craig Gilroy and Iain Henderson was a key element in the 53-0 win at Thomond Park in Limerick.
"I was quite proud of the performance of the squad," said Heaslip.
"It was a privilege to lead out a side that was full of such an enthusiastic bunch of guys.
"We talked all week about focusing on our roles and getting the details right. I said during the week that we have been training really well and, against Fiji, we played how we trained. We didn't get any return last week (against South Africa) but I was quite proud to see the return we got this week."
The wounds of a 60-0 mauling at the hands of New Zealand on their summer tour have not healed completely. Heaslip believes shutting out an attack-hungry Fiji team bodes well ahead of Argentina's visit to Dublin on Saturday.
He said: "I'm more pleased with the zero (conceded) than the amount of tries we scored, to be honest. It is really hard in international rugby, to be able to shut a team out and give them no scores at all. That zero was ... I'm more proud of that than the scores.
"It would have been really easy to take the foot off the gas coming into that last quarter but credit to the lads for not doing so. Fiji kept the pressure on and had a good bit of ball near our line but guys stepped up, put their bodies on the line and stepped up at pretty significant times."
No Test caps were handed out for the fixture but players such as Henderson, hat-trick star Gilroy and Luke Marshall have thrown their names into the selection mix for the Argentina Test.
Heaslip remarked: "We've talked a lot about owning that jersey for a day and even though it wasn't a full Test, for some of the younger guys, they really stepped up to the mark as if it was a full international. They did the jersey proud."
Coach Declan Kidney admitted that he "certainly had a few selection choices" to make before the Argentina visit.
"It's a new time for Irish rugby," he said.
"There's a whole new squad coming through and some fellas got their chance and showed that they want more of it.
"It certainly makes going to work easier on Monday when you've got a win," he added.
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