Japan all but sealed their place in the Women's World Cup last 16 on Wednesday with Spain poised to fire a title warning and join them in the knockout rounds.
The 2011 champions Japan easily beat an error-prone Costa Rica 2-0 in front of 6,992 spectators in Dunedin -- the smallest crowd at the tournament yet -- to stand on the verge of qualifying for the next stage.
Spain, one of the favourites to take the title off the United States, will be expected to send themselves and Japan through when they face minnows Zambia in the next match of the day.
They will be the first teams to get out of the group stage.
Japan began their campaign in Australia and New Zealand by thrashing Zambia, the lowest-ranked team in the tournament, 5-0.
It would be a major surprise if Spain do not give Zambia the same kind of punishment.
Japan were never in trouble against an outclassed Costa Rica at the nearly 30,000-capacity Dunedin Stadium, where there were rows of empty seats for a game that kicked off at 5:00 pm (0500 GMT).
The game was effectively killed off in the space of three first-half minutes.
Hikaru Naomoto fired Japan ahead on 25 minutes after the Costa Rica defence went AWOL and her shot squirmed underneath goalkeeper Daniela Solera.
Solera was at fault again just two minutes later, allowing Aoba Fujino's shot to go in at her near post.
In the last match of the day, in Perth, Olympic champions Canada face World Cup debutants Ireland.
The 40-year-old Christine Sinclair will become the first man or woman to score at six World Cups if she gets on the scoresheet.
Fight to the end
Thursday's action is headlined by a heavyweight clash between the United States and the Netherlands in Wellington.
Both teams will expect to get out of Group E, so bragging rights and group supremacy are at stake in a re-run of the 2019 final.
On that occasion the Americans won 2-0 and are now pursuing a third World Cup title in a row, something that has never been done.
The Netherlands are not quite the force they were, having lost Sarina Wiegman as coach and missing star striker Vivianne Miedema, who is recovering from a serious knee injury.
But current coach Andries Jonker believes the rest of the world, the Dutch included, are closing in on the United States.
"This is the development of women's football," he said.
"Are we getting closer? The feeling is yes. Tomorrow is the first time we can check if we are closer or not."
Jonker is anticipating a game of what he called "modern women's football -- a fight from the first minute to the last".
"We both need a win again, both want to win the group, so it's going to be a really good match."
Also on Thursday, co-hosts Australia play Nigeria and must do so with only one recognised striker after Manchester City's Mary Fowler was ruled out of the match with concussion.
The Matildas were already missing captain and talismanic striker Sam Kerr, who was ruled out of at least the first two matches of the tournament with a calf injury.
Arsenal's Caitlin Foord is now Australia's only recognised fit striker.
