REIMS, France — Last fall, when Jill Ellis was involved in arranging tuneups for her U.S. national soccer team leading to the Women’s World Cup, many obvious opponents came to mind.

Certainly the Americans would play an away friendly against France, host to this summer’s tournament. Usual suspects, such as Brazil, Japan and Australia, were on the agenda as well.

But with women’s soccer experiencing growth spurts, Ellis also wanted to gain a firsthand look at a World Cup-bound team from a traditional soccer country emerging in women’s circles.

So in January, the top-ranked Americans played Spain for the first time, visiting the city of Alicante on the Costa Blanca. Spain is among the giants of the men’s game, not the women’s, but times are changing.

“It was actually purposeful why we wanted to play them early in the year,” Ellis said Thursday after her team completed a perfect group stage. “It was great to get them on the schedule and experience that in their home country.”

Five months later, Ellis is hoping that maiden encounter against Spain will prove beneficial as the sides prepare to meet again Monday in the round of 16 at Stade Auguste-Delaune.

The United States secured this matchup with a 2-0 victory over Sweden that secured first place in Group F.

As women’s soccer evolves, the long-term threat to the game’s standard bearers comes from countries such as Spain and the Netherlands.

Consider the 13th-ranked Spaniards, who are appearing in their second World Cup.

Though a championship run is years away — and the hopes of upsetting the top-ranked Americans are thin — the building blocks are in place.

Pro clubs that employ the majority of the 23 players on the roster here include FC Barcelona (10), Atletico Madrid (five) and Paris Saint-Germain (one). All are among the wealthiest organizations in global soccer.

Imagine if Real Madrid, the sport’s richest operation, made any kind of commitment to the women’s game. (It doesn’t even field a women’s team.)

Traditional clubs offer prestige, world-class facilities, development opportunities, high-level coaching and, most importantly, the money to do it all.

Even if support for a national team from the domestic governing body is lagging, the talent cultivated by the big clubs inevitably will deepen the national team’s talent pool and improve results in major tournaments.

Barcelona, an UEFA Women’s Champion League finalist last month, and Atletico Madrid, the three-time Spanish women’s league champion, are among the biggest names in the sport at large.

Because of Spain’s rise — as well as the emergence of women’s teams from other soccer hotspots — the sport has grown more complex.

“We know they are good on the ball,” U.S. forward Carli Lloyd said. “We know they are technical.”

In the winter friendly, Spain impressed with its ability to link passes and move the ball fluidly through midfield. Upon approaching the penalty area, however, things fizzled.

That inability to punish teams has left Spain lacking, not just in that friendly — U.S. substitute Christen Press scored the lone goal in the second half — but in the World Cup. In a 3-1 victory in the Group B opener against South Africa, two goals came on penalty kicks. (Spain enjoyed 72 percent of possession.)

In the subsequent two matches, the team failed to score.

It kept 59 percent of possession in falling to two-time World Cup champion Germany, 1-0, and 61 percent — and a 24-1 shot advantage — during a 0-0 draw against China.

“At least we’ve shown what Spain can do on the pitch,” Coach Jorge Vilda said after the Germany outcome. “We were playing good football, but mistakes cost us dearly. We were able to dominate them in certain parts of the match. Obviously we weren’t able to put the cherry on top of the cake, but we were able to bring that style of play.”

That possession-oriented style — synonymous with Spanish men’s soccer, particularly at Barcelona — was among the reasons Spain was forecast to advance out of group play this summer after struggling in its World Cup debut four years ago in Canada, losing twice and drawing once.

The program has made progress in Europe — 17 wins and a draw in 18 matches with a 67-4 goal differential in the past two World Cup qualifying cycles — but has never played in the Olympics and is a relative newcomer to the world competition.

As the program has grown, however, Spain has earned better results against established teams. Aside from staying competitive against the United States early in the year, the Spaniards prepped for the World Cup by playing six France-bound teams — victories against Brazil, England, Netherlands and Cameroon, and draws with Canada and Japan.

The United States has yet to face a team here that possesses the ball so well: Thailand and Chile rarely crossed the center line, and Sweden registered only slight success in attempting to break down the U.S. defense Thursday in Le Havre.

For the first time in their World Cup history, the Americans did not concede a goal in group play.

Spain, a fresh face on the scene, will offer a different type of test for the seasoned Americans, who, to this point, have dominated at both ends.

Ellis said, “Any team that gets out of their group and is in this position, I 100 percent respect.”

Read more: