Montoya ran out for his 100th cap in the clash in Santa Fe but few, if any, would have had as dramatic contrasts as the thrilling victory over the Wallabies.
The skipper was among the try scorers as Argentina came back from a 17-point deficit to record their biggest win in 13 years of participation in the annual southern hemisphere championship.
"It was a match that went from less to more," he told reporters. "The important thing was taking a step forward as a team, especially compared to last week."
Argentina lost to a last gasp kick to Australia in La Plata last Saturday where the rainy conditions contrasted with the brilliant sunshine of Santa Fe.
"We did things well in the first half, with some mistakes. We continued to trust in what we were doing, and we improved in the second half, where we saw the spaces."
Montoya's try just before half-time would have helped with the mental switch as 20-3 to Australia after 30 minutes became 20-17 at half-time.
After the break, there was no stopping the Pumas. "We tried to go action by action, without thinking about the result. We are far from perfect, but I'm proud of how we went about it," Montoya added.
"We've had a great week, we have to enjoy it and there are many things to correct. We are a very ambitious group. We owed ourselves a debt. We channelled the opportunities and today we were better than last week. We are still not where we want to be, but without a doubt this is the way."
Montoya, who turns 31 next month, reflected briefly on his century of appearances.
"My dream was always to play a game for the Pumas. I've reached 100, and in this squad I've learned a lot. I'm very happy. The important thing is the shirt and the team. Today I'm here, but tomorrow maybe not."