"I think they've found out what it's like to play international," said the 52-year-old of New Zealand who have midfielders Stephanie Dickins and Tessa Jopp, along with goalkeeper Grace O'Hanlon, making their debut.
Argentina, he said, were one of the best teams in the world so it was a good challenge for the tourists.
"It's a good wake-up call. Sometimes we think we're doing okay, you know, but you find out you have a lot of things to work on."
Hager said the Argentines had the propensity to punish any team.
"From what I've seen we've struggled to put passes together because Argentina backs are so good at tackling."
That's why the Vantage Hawke's Bay Hockey Festival will become an ideal platform, via the Hawke's Bay Cup competition, for the world No 5 women to refine those aspects of play against other international teams from March 31 to April 9 at the Unison Stadium at the HB Regional Sports Park in Hastings.
Australia are No 4, the USA No 6 and Japan No 11 although the Kiwis are the defending champions.
"When I first came here post-London and now post-Rio we've had such a huge turnover so that means the exciting thing is can we keep going and push to make the top-four spot in the world which is the key.
"They need to challenge themselves to be better and not just a Black Sticks player. You want to be one of the best in the world, not just as a team but as individuals so I think that's the one thing we need to strive for."
The FIH Home and Away League, should New Zealand be successful, will elevate the Hawke's Bay Cup from 2019.
The International Hockey Federation (FIH) has shortlisted 18 nations, including New Zealand, as candidates for the men's and women's leagues.
While Hager gave it a thumbs up he treaded cautiously on the logistics of travel involved.
"We can't afford to go to Europe three or four times in a year so for them to come our way is going to help."
No doubt to play on home soil in front of fans also is exciting.
He had pondered after Rio on whether he should remain with the Sticks women after an eight-year stint.
"I thought was it time for a change for both parties but I looked at what we had in the Black Sticks and thought we still had a good group and I felt we're still capable of doing good things."
The disappointment of missing out on a medal at the Olympics only made the Australian's resolve stronger in returning to complete unfinished business in four years.
Hager's Lancers are in the final at the weekend but they won't know who their opponents are because some games have yet to be played.
"I probably learn a lot more from the different nationalities," he said of the Lancers who were runners-up in the HIL last year.
Moritz Fuerste, a German, is captain. Adam Dixon, a fellow midfielder, is an Englishman, Billy Bakker is from the Netherlands, four players are Australians and the rest are Indians in the 20-member squad.
"I have heaps of different styles - different way the men play, different way Germany play to England to India so it's a good sort of education to just coaching a men's team."
The Lancers are partial to the German style where Fuerste keeps it pretty simple.
"Everybody has their different ways so it can be a little difficult at times but it's exciting."
Hager said the India league was fantastic because when they played their home games at the Kalinga Stadium, Odisha, they had 6000 to 10,000 fans watching them.
"They are very vocal so they're fantastic," he said, enjoying the top-class accommodation, food and hospitality.
Last year he took bits and pieces from the India league to the Black Sticks women's campaign to Rio Olympics.
"This time around I'll go in a little more confident in my coaching and we'll try a couple of different things and some things work and some things don't so it's a good opportunity to try things and then bring them back to the Black Sticks to see if they work with us as well."
The Star sports TV channels are accessible to Europe, Australia and New Zealand, something Hager felt would be great if it happened via the Home and Away League.
Last year Hager was rushed to hospital for a check up after complaining of chest pains in Hastings.
"There's nothing wrong with me at all. It was just a bit of a cramp and a bit of a scare," he said with a laugh from India before he jets back home early next week.
