Tietjens said giving all of his squad a gallop in pool play would help shape his thinking for who he would select when the pressure went on in the knockout stages today, starting with a quarter-final against Australia at 2.31pm.
"It'll be quite clear in my mind who starts the quarter-final," Tietjens said.
"They can all come out of that with a good, fair idea of who's really up for it because when it comes down to bringing guys off the bench in big games.
"I've certainly got to know who can perform and who can't."
New Zealand, who are in third on the overall standings in the world series, were hurt this week by the loss of veteran Tim Mikkelson (groin injury) but Tietjens was full of praise for his youthful quintet.
"They're not overawed by the occasion and they're playing particularly well," Tietjens said.
The obvious talking point from yesterday came from the amount of empty seats on show and organisers said only 15,000 people came through the gates at Westpac Stadium, well under its capacity of 34,500.
Tighter restrictions on drinking, a congested events market and a tired business model had all contributed to the decrease in popularity for the event but it came back to earth with a thud yesterday after previously being a must-attend weekend.
In Pool A, world series leaders South Africa survived their opening loss against France to finish second in their group after they tipped over USA 26-14 in their final pool game.
The US topped their group for only the second time in the world series, and the first since 2001, and they will meet Scotland in their quarter-final today, while South Africa will face Kenya who emerged top from Pool D.
England, who finished second in Pool B behind New Zealand, will meet Pool C winners Fiji.
Fiji, who are in second place on the world series standings, looked at their dominant best yesterday as they went through pool play with three wins from as many games.
France, Japan, Canada, Papua New Guinea, Wales, Portugal, Argentina and Samoa all missed out on the quarter-finals and will fight out the minor trophies today.
Wellington is the fourth of nine in the world series. The circuit moves to Las Vegas next weekend.
Top results
New Zealand 24 England 5
France 22 South Africa 5
New Zealand 26 Canada 5
England 90 PNG 0
England 27 Canada 6
Fiji 42 Wales 19
Scotland 14 Samoa 12
Australia 36 Wales 5
Argentina 21 Samoa 21
New Zealand 38 PNG 7
Fiji 14 Australia 5