As we previously reported ... 2 former LSU students told USA Today Sports that the former Tigers superstar RB raped them at their own apartments after nights of heavy drinking.

One of the women says she passed out on her bed and has flashback memories of Guice assaulting her.

She also says it was all particularly troubling because her boyfriend at the time was Guice's teammate on the LSU football team.

In the report, the boyfriend alleged Orgeron had at least some knowledge of the incident ... and says the coach brushed it all off to him when they had a conversation about it.

In fact, the boyfriend said to USA Today Sports that Orgeron had told him, "everybody’s girlfriend sleeps with other people."

Orgeron, however, fired back at the report in a lengthy statement Thursday night ... saying he had absolutely ZERO knowledge of an alleged Guice assault.

"The anonymous quote attributed to me by a former player in USA Today is not accurate," the coach said. "Out of respect for the young man's privacy, I will not reveal the full details of the conversation. What I will say is that a player came into my office to discuss transferring from our program."

"We also discussed the player's relationship challenges with his girlfriend. I told him what I would tell my own sons: 'We all experience heartbreak growing up. Do not throw away a promising academic and football career at LSU because of a personal obstacle.'"

"Any insinuation that I had knowledge of his girlfriend and Derrius Guice is completely false."

Orgeron added that he is complying with investigators ... saying, "The sexual assault allegations made against Derrius Guice should be taken very seriously and the alleged victims must be heard and supported."