Henry opted for an experimental backline for the World Cup's opening match to shake up the All Blacks after their loss to Australia in last month's Tri-Nations decider.
Williams started at inside centre — shifting Ma'a Nonu one spot wider — and Dagg started at fullback, the recalled pair forcing out Conrad Smith and 98-test veteran Mils Muliaina. Dagg, returning to form after a serious thigh injury, had a terrific game in the 41-10 win and must be a strong contender to take over as the All Blacks' first choice No. 15.
"I think he played pretty well, really," Henry said of Dagg. "I think he'll be pleased with the way he played. A couple of decision-making errors late in the game, but I guess he's only played two games in the last three or four months, so he probably ran out of a bit of steam at the finish."
"He's a threat," Henry added. "He creates. He was the last-passer on a couple of tries, so he'll be pleased."
Williams also got off to a sizzling first half, with one sensational behind-the-back pass creating one try, and a diving, one-handed offload setting up another for Dagg in the left corner. In the second half, however, he made a couple of mistakes when he tried to do too much. Williams has acknowledged in the past he sometimes gets overexcited and has been trying to tone it down.
Henry also praised the rugby league-convert's efforts, but didn't didn't give any indication about who he favours for his starting line up in New Zealand's second match against Japan next Friday. He has said he doesn't want to tinker too much with his combination.
Dagg was fairly critical of the team's performance, despite the opening win.
"We were kind of pushing a few passes and didn't build enough pressure. We didn't show them enough respect, I think," he said. "I just think we tried to go around them too much instead of just working hard and going through. We've just got to go back to the drawing board and train hard this week."
Dagg said playing in the opening game in New Zealand was an honour.
"The first game is always a nervous one," he said. "It was a great atmosphere out there, doing the anthems and the haka in front of that crowd was a pretty special moment — I'll cherish that."
Henry may be tempted to continue his backline experimentation against Japan but he'll want to be well settled on his lineup by Sept. 24, when the All Blacks face two-time finalist France, the team which has eliminated them from two of the last three World Cups.