The events of August 20th eclipsed the national women team's World Cup victory in Sydney and led to protests similar to the MeToo movement, prompting other women to come forward with reports of sexist treatment and assaults.
It also sent a shudder through the male-dominated ranks of Spain's football establishment.
Rubiales has maintained that the kiss was mutual and consensual. After weeks of resisting calls for him to step down as president of the Royal Spanish Football Federation (RFEF), Rubiales, already suspended by FIFA, finally quit on September 10th.
But he remains unrepentant.
"I am a good person, that in a moment of maximum happiness, with consent, asking beforehand...In truth, there can be no other intention than the celebration and the joy itself," he told British television interviewer Piers Morgan on Sunday.
He likened the celebratory atmosphere in Sydney to winning a lottery or seeing a war ending, situations in which he said "people don't ask permissions".
Deputy Prime Minister Yolanda Diaz has called his actions "shameful" and said they showed that male chauvinsim was stil systemic in Spanish society.
Complaint filed
On September 8th, prosecutor Marta Durantez Gil filed a complaint with the High Court against Rubiales after Hermoso told prosecutors that Rubiales kissed her on the mouth without her consent while holding her head with both hands at the medals ceremony.
The prosecutor added a possible crime of coercion after Hermoso said she and her relatives were put under pressure by Rubiales and his entourage to say that she "justified and approved what happened".
Judge Francisco de Jorge is in charge of an investigation that has to precede any formal charges under Spanish law, and will decide whether the case will go to trial. If it does, he could face between one and four years imprisonment.
De Jorge has ordered several media, including state broadcaster TVE, to send him footage of the incident and subsequent videos such as one of the players celebrating on a bus with Rubiales and referring to the kiss in what appeared to be a light-hearted manner. The investigation could take several months.
Friday's hearing is behind closed doors.
The legal case will also be a public test of the leftist coalition government's flagship "Solo si es si" (Only yes is yes) law that puts consent at the heart of sexual relations.
Many players, sports bodies and politicians have backed Hermoso in a campaign coalescing around the hashtag #SeAcabó (It’s Over) on social media, showing the nation's increasing intolerance to abuse.
Spain's top 87 female players, including the 23 world champions, have refused to play for the national team until there are changes in the RFEF management line-up and style.
The RFEF has since sacked women's team coach Jorge Vilda (42), appointing his assistant Montse Tome (41) instead as the first woman at its helm.
Left back Olga Carmona (23) said this week that the players were yet to determine if changes were enough for them to return to the team.
