New Zealand have just completed a series against world No 2 Australia, drawing twice and losing once, but scoring seven goals in the process and knowing they were 17 seconds away from levelling the series in the third game in Wellington this week.
That experience should help the learning process though, as the Black Sticks were unable to retain possession to see out the remaining seconds when holding a 3-2 lead.
After goalkeeper Sally Rutherford, 33, captain Anita Punt and fellow midfielder Petrea Webster at 26 are the oldest players in the group.
Time is on their side and Hager liked much of what he saw in the series, but acknowledged more work must be done in defensive situations and capitalising on penalty corner chances.
New Zealand, ranked fourth in the world, are grouped in pool A with world champions the Netherlands, China and Japan.
The Black Sticks will be up against it when they face the Dutch, who they have never beaten.
But China and Japan, who finished sixth and 10th at the World Cup in mid-year, are certainly beatable.
They have two warmup internationals against hosts Argentina next week, and a practice game against Germany.
These games will be invaluable in getting the players immersed into tournament thinking and strategies.
The only injury concern is Canterbury attacker Sophie Cocks, who took a blow on a foot against Australia and is likely to play little role in the practice matches.
Teams in pool B are Argentina, Germany, Australia and England.
The players
New Zealand squad for the Champions Trophy in Mendoza, Argentina:
Anita Punt (c), Aniwaka Roberts (Capital), Liz Thompson, Julia King (Auckland), Petrea Webster (North Harbour), Georgia Barnett, Michaela Curtis (Central), Ella Gunson, Stacey Michelsen, Brooke Neal (Northland), Sam Charlton, Sally Rutherford, Rose Keddell, Shiloh Gloyn (Midlands), Sophie Cocks, Jordan Grant, Pippa Hayward, Olivia Merry (Canterbury).
The timetable
New Zealand schedule (all NZT)
Nov 30: v Japan
Dec 1: v Netherlands
Dec 3: v China
Classification games from Dec 5
