The 27-year-old starred on the wing for Joe Schmidt's men as they romped to victory over Scotland on Saturday, but now returns to Leinster to try and help the men in blue to their third successive GUINNESS PRO12 title.
Munster's JJ Hanrahan will be the only elite Irishman playing his rugby outside of the GUINNESS PRO12 after his move to Northampton this summer, and Fitzgerald believes the progress made by the Irish league teams in recent years have been a big factor in the international team's run of form.
"It's probably hard to put it down to just one thing," he told the Irish Times. "But Joe Schmidt and Paul O'Connell have said the provinces do a fantastic job in the GUINNESS PRO12.
"I think there has been a pretty high level of consistency over the last 10 years.
"Now the expectation will probably be very high for the World Cup for Ireland and I think it should be.
"What is good is we went out there and we put it on the line. I mean often times you tighten up in those scenarios and I think it's a real lesson for any team going forward.
"Try it. If you fail trying, there's absolutely no shame in that. At least you gave it a shot."
Fitzgerald also highlighted the performance of Leinster team-mate Jamie Heaslip, whose superb covering tackle on Glasgow Warriors' Stuart Hogg late in the game against Scotland made all the difference for the Irish.
He said: "I feel pretty strongly that there was absolutely no luck involved.
"Jamie could have left that, it would have been a try and nobody would have said anything. That was just pure work ethic there and good habits ingrained in a guy."
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