The Kiwis opened their tournament with a 42-24 win over Toa Samoa, racing out to a 36-4 lead before watching the margin trimmed to 12 with 15 minutes to go.
Luckily for the defending world champions, Toa Samoa were unable to complete the comeback but Whare, who was named man of the match, said his team would be foolish not to learn their lesson.
DEAN WHARE INTERVIEW
In the first half there, we were very strong and dominant, said Whare.
Its just being more consistent there for the whole 80 minutes. Up to the latter stages, we cant come 20 minutes in, 20 minutes out.
When you come up to Australia and England, theyre going to take those opportunities and waltz away if you dont learn from those mistakes.
Appearing in just his fourth Test for New Zealand, Whare, 23, made a game-high three line breaks, ran 126m, set up a try and had a hand in another.
You cant play bad when youve got Sonny Bill [Williams] and Shaun Johnson inside you giving you early balls, Whare said.
Credit to the team, most of it goes to our forwards. In the first half, they were laying a great platform for us and all we had to do was finish it off on the edges.
The Kiwis take on France in Avignon, France early tomorrow morning (9.00 NZT) before their final group game against Papua New Guinea on November 9 (NZT)
A win against the French, who scored a thrilling 9-8 victory over Papua New Guinea in their first game, would secure a spot in the quarter-finals.
Squad members not used in the Samoa win - Greg Eastwood, Alex Glenn, Krisnan Inu, Kevin Locke, Ben Matulino and Jason Nightingale - are all lining up for their first appearance of the tournament.