Japan are firming their status as one of the favourites to win the Women's World Cup after romping into the quarterfinals with four dominant wins and 14 goals scored over four games.

Coach Futoshi Ikeda, however, spent much of his post-match press conference after Saturday's 3-1 win over Norway discussing the single goal his team have conceded in their time in New Zealand.

Having kept three clean sheets in the group stage, the Nadeshiko defence was finally breached in the 21st minute on Saturday by an equaliser of the highest quality from Norway's Guro Reiten.

Ikeda said he felt the defensive line had perhaps been a little too deep in the early part of the game and said he would discuss it with his defenders to understand why that had happened.

Most of all, though, he was delighted that the setback had not appeared to impact the morale of his youthful team, who scored two second half goals to set up a last-eight clash with reigning champions the United States or Sweden.

"This is knockout stage and we knew that it was going to be a tough match," he told reporters.

"We all wanted to win and when Norway scored, the players were still very positive, and we kept our focus and kept up the pace. And in that sense, I think we have become a bit tough, even tougher than before."

In keeping with the team ethos, there was no individual mention in his press conference of Hinata Miyazawa, who scored her fifth goal of the tournament on Saturday to move to the front of the race for the golden boot.

When told that Norway's Caroline Graham Hansen had said Japan were now the team to beat, Ikeda merely reiterated that the Nadeshiko would be taking it one game at a time as they seek a second world title after their 2011 triumph.

Norway coach Hege Riise, a World Cup winner as a player in 1995, was a little more detailed in her response when asked whether Japan were the best team at the tournament.

"I've seen them play the group stage and they are great team with a lot of good players and tactics," she said.

"The combination of tiki-taka ... combined with the direct play, it's hard to defend. They (need to) continue to play their own game."