Fitzgerald puts this sharpness and effectiveness in the tackle down to his work with Ireland defence coach Les Kiss, who has come in for universal praise from the Irish players since he joined the set-up last year.
"I think Les is fantastic. He's brought so much to the set-up. Defence is his main area and he's been brilliant for us there," admitted Fitzgerald.
"He has an awful lot of new ideas and new thoughts on how to stop teams breaking us down.
"He has a few interesting things to say in terms of attack as well. He's a really interesting guy to talk to about the game."
The 21-year-old credits Kiss with specifically improving his approach into the tackle and helping to better his overall technique.
"I've seen a big improvement in the last year in terms of what I can add to the team defensively.
"That was one of the areas that I had marked out as something that I really needed to improve in my game.
"I never thought there was a lack of intent there. Just maybe some technique and stuff needed to be improved.
"I'm happy with how I'm progressing with that side of things. Les has had a big impact on me in terms of my thought processes going into tackles as well."
The Ireland players had a short break after the 38-9 win over Italy and were back in camp last night (Wednesday), which for this week is down in Cork.
As seen during the Italian match and afterwards as he talked to the media as the man-of-the-match winner, Fitzgerald is a confident young man and not afraid to tell it how it is - win, lose or draw.
A few months on from the November Tests and Declan Kidney's debut as Ireland coach, it is clear that things are beginning to click for Ireland both on and off the pitch.
Fitzgerald gave an insight into the mechanics of Ireland under Kidney, pointing to the productive team meetings when the squad were holed away in Enfield pre-Christmas as to where the groundwork for this current campaign was laid.
Looking back at the progress made, he said: "I thought the criticism of the team was quite harsh after the autumn internationals.
"I think that the coaching staff didn't have that much time to get us ready and we hadn't got used to each other.
"I don't think that there was a total understanding of what the coaches were trying to get across to us in terms of how they wanted us to do things in certain areas of the park.
"I'm not too sure, too, if they understood how we wanted to play the game. I think it's very important to have that understanding. We've built that with that extra time we've had.
"We didn't do much on the pitch, just had an awful lot of meetings (pre-Christmas) and it kind of cleared the air.
"I thought we came out of those meetings with an awful lot of focus and an understanding of what we wanted to achieve on the pitch - from both the coaches' and players' perspectives.
"I think that's really helped us. I don't think you can put it down to just one thing but that's one thing that's really helped us," he added.