The first accuser in the Kellen Winslow Jr. rape case is on the stand -- telling the court in graphic detail how the ex-NFL star raped her and then threatened to kill her in a supermarket parking lot.
The woman -- identified only as Jane Doe #1 -- is one of 3 accusers claiming she was raped by Winslow. Two other women in the case claim Winslow exposed himself in front of them.
During Tuesday's hearing, Jane Doe #1 -- a 54-year-old woman -- says she was hitchhiking in San Diego in 2018 when Winslow picked her up in a nice Jeep and took her to a Vons supermarket parking lot.
The woman says 35-year-old Winslow essentially mounted her in the car and forcibly raped her, causing her to bleed all over the place.
She claims Winslow eventually let her go but threatened her -- saying, "I'm going to f*cking kill you if you say anything and I'm going to kill you."
She added, "He threatened to kill me, and I really believe he would have."
Winslow is sitting in the courtroom and facing his accuser. He has previously denied ALL of the allegations ... insisting, "I am an innocent man."
He's facing multiple felony charges including kidnapping and forcible rape. If convicted on all counts, he faces life in prison.
Winslow was initially arrested back in June 2018. Officials say he kidnapped and raped 2 transient women. A 3rd woman claims Winslow raped her 15 years ago while she was unconscious.