"It's about giving some opportunities to players, and they've deserved it I might say," Hager said.
"They've performed pretty well so far in the three games. That's the good thing; we've got such good competition among the girls, they're pushing each other really hard. They are good friends but competitive and driving each other to be better, which is pleasing."
Hager knows heartache is around the corner for some players but better to have to make those decisions than scratch around and try to find sufficient quality to produce a competitive squad for Rio.
Long time captain Kayla Whitelock is coming right, Hager said. She has been out for over a year since the Commonwealth Games in Glasgow in 2014 and having her first baby.
"She's played the three games so far and is still finding her feet a bit in the tempo of the game. But she showed some good signs today.
"She gives us that strength to hold the ball and produce good quality passes," he said.
Whitelock is being used in a more advanced position on the field than in previous seasons. That's partly to give more stability up front and help create goalscoring chances, but also is a show of faith in the defensive players.
''We're getting more confident with the people in the back half, like Sam Charlton, Pipa Hayward, Ella Gunson and Emily Naylor. Add in Stacey Michelsen, Liz Thompson and Brooke Neal and we've got some really good quality players there," Hager said.
Petrea Webster, Sophie Cocks and Kirsten Pearce, with a deflection in the final minute, got New Zealand's goals.
Game four in the series is on Monday, also in Mar del Plata.