Mac Allister did not play Argentina's first game in Qatar, a stunning 2-1 defeat to Saudi Arabia, but has subsequently cemented a place in Lionel Scaloni's midfield and quickly emerged as a key player.
Argentina takes on the Oranje at Lusail Stadium with a place in the semi-finals at stake and Mac Allister is excited at the prospect.
"If you would have told me this [how influential he has become] before the World Cup I would have signed up for it, for sure," he said.
"It has been a fast integration but the credit for that goes to my colleagues and the technical staff."
The Netherlands will pose a serious threat to Argentina's hopes but Mac Allister was more interested in talking up his team-mates than spending too much time worrying about Louis van Gaal's men.
He said: "We know they have great players, and a very clear style, but we have our own weapons and will try to counter theirs.
"There is a great history between the sides but if we do things right everything will be fine."
The nations have met five times previously at the World Cup, with the last coming in 2014 when Argentina won a semi-final clash in Brazil on penalties after a turgid 0-0 draw.
Van Gaal was also in charge of the Dutch on that occasion, during his second spell of three at the helm, and Mac Allister was full of admiration for the 71-year-old.
"I remember watching that game with my family at home," he said. "I enjoyed it and now I am here. Being able to play these matches is a great joy.
"We know he's a top coach, world renowned, and there is a great deal of respect from everyone in our camp, including me. His teams always have variation but with a clear idea. We are up against a great team."
Lionel Messi has been Argentina's standout player so far in Qatar and stopping him could be key to the outcome.
Reports in the Netherlands suggest Van Gaal is considering employing someone to man mark the Paris Saint-Germain star but Argentina boss Lionel Scaloni claims to have seen it all before.
He said: "We are used to our opponents coming up with something different. We will see but, during the match, there are always modifications, and that’s something we are likely to do as well.
"Let's wait and see but we have played matches before when there has been man-marking on Leo."
Argentina has injury concerns over Rodrigo De Paul and Angel Di Maria but Scaloni was not giving much away regarding its availability.
"Today we have the last training session so we will see how they feel," he said. "Rodrigo trained on Wednesday so let's see what happens in today's session. Angel also trained so we will decide later today."