The United States District Court for the Central District of California granted a motion for class certification in the ongoing gender discrimination lawsuit between members of the U.S. women's national team and the United States Soccer Federation, handing the players an early procedural success.

Judge R. Gary Klausner ruled Friday that the plaintiffs can proceed with certification that names Carli Lloyd, Alex Morgan, Megan Rapinoe and Becky Sauerbrunn as class representatives. The class includes players who appeared for the national team dating back to Feb. 4, 2015.

Certifying a class would allow the players to argue their case as a group and allow any players to opt in to the class. Those who don't opt in can still sue on their own.

"We've sort of learned in this whole process there are all these steps you have to go through and different things mean different things and sometimes you don't know the context or the gravity of things," Megan Rapinoe told ESPN.com. "But this is a really big one. For us, personally, to feel from someone very important to the case, the judge, the sense of validation in what we're saying and the case that we have.

"From a legal perspective, I think it's a huge step forward for us."

In making the ruling, which was on the procedural question and not specifically the merits of the lawsuit, the judge nonetheless rejected several arguments made in U.S. Soccer's motion to deny certification. Most notably, that the four proposed class representatives lacked standing because they earned more than men's national team players during the period in question.

The Court cited previous rulings involving both the Equal Pay Act and Title VII of the Civil Rights Act of 1964, under which the players brought the lawsuit, that discrimination involves rates of pay and not the total income earned. U.S. Soccer had argued in the motion to deny class certification that because the players earned more total income, they did not suffer legal injury.

"Further, courts interpreting the EPA and [to a lesser extent] Title VII have explicitly rejected this argument - for good reason," Friday's ruling stated.

The Court also rejected U.S. Soccer's assertion that the plaintiffs provided "insufficient proof" for the contention that unequal working conditions -- including inferior playing surfaces, lower ticket prices, fewer marketing resources and fewer charter flights -- constitute "concrete" legal injury.

According to the judge's written ruling, agreeing with U.S. Soccer's argument could yield an "absurd result," in which a woman could be paid half as much as a man as long as she negated the disparity by working twice as many hours.

"This is a historic step forward in the struggle to achieve equal pay," said Molly Levinson, spokesperson for the plaintiffs. "We are so pleased that the Court has recognized USSF's ongoing discrimination against women players -- rejecting USSF's tired arguments that women must work twice as hard and accept lesser working conditions to get paid the same as men. We are calling on Carlos Cordeiro to lead USSF and demand an end to the unlawful discrimination against women now."

U.S. Soccer was not immediately available for comment on the ruling. At an Oct. 28 press conference to introduce Vlatko Andonovski as the new coach of the women's national team, federation president Cordeiro was asked about the status of the lawsuit.

"I will just reiterate what I have said in the past," Cordeiro said. "Which is the federation has always been committed to paying our players, our senior national team players -- both our women and our men -- fairly, equitably, regardless of gender."

Mediation between the sides broke down in August. The suit remains in the discovery phase, and U.S. Soccer last week filed a motion for the disclosure from players of all soccer-related income that did not come from U.S. Soccer.

A trial is current scheduled to begin May 5, 2020.