(CNN) -- More prosecution witnesses are expected to testify Thursday in a marathon 11-hour session in the rape trial of two Steubenville, Ohio, football players accused of sexually assaulting a 16-year-old girl.

The trial, which is likely to stretch into the weekend, is moving quickly to accommodate the schedule of visiting Judge Thomas Lipps, who is presiding over the trial without a jury. A verdict is expected by Sunday.

Prosecutor Marianne Hemmeter opened the trial Wednesday saying the defendants -- Trent Mays, 17, and Ma'lik Richmond, 16 -- treated the girl "like a toy" with a string of degrading acts during a series of end-of-summer parties in August.

The teens are charged with rape. Mays is also charged with illegal use of a minor in nudity oriented material. Defense attorneys say the two are innocent.

According to prosecutors, Richmond and Mays each penetrated the victim's vagina with their fingers, an act that constitutes rape under Ohio law.

They are not accused of having intercourse with the girl, although Hemmeter said in opening statements that one photograph appears to show semen on the girl's body and DNA analysis of semen found on a blanket she was lying on was a match for Mays.

Some of the alleged abuse was captured in cellphone images circulated in text messages and on the Internet, raising the profile of the case and bringing national attention to the town.

The case will hinge not on consent, but rather whether Mays and Richmond knew the girl was too impaired to know what was happening the night of the alleged attacks, Hemmeter said in opening statements Wednesday.

The girl, Hemmeter said, was "too impaired to say no, too impaired to say stop."

Six witnesses for the prosecution testified Wednesday, saying she appeared to be drunk -- stumbling, swaying and throwing up.

One witness, a 17-year-old girl who went to a party with the alleged victim, said she and the girl shared a half a bottle of vodka, which they each poured into a flavored crushed ice drink.

The alleged victim also had a beer and seemed to get drunk very quickly, the witness said.

The party broke up about 12:30 a.m. and the girl left with Mays and Richmond, according to the witness -- who said she pleaded with her not go. The witness said she didn't see the girl again until the next day when she picked her up at another home.

She described the girl as a "mess," wearing her stained shirt inside out.

On cross-examination, Richmond's attorney, Walter Madison, asked the witness if her view of what had happened that night had been framed by the tweets and social media posts she had seen about the victim, and if what she had seen in those messages made her angry.

The girl said it had.

Another witness, a 17-year-old friend of Richmond, said on cross-examination that while the girl appeared drunk, he did not believe she was unaware of what she was doing.

The boy also told Mays' attorney, Brian Duncan, that he hadn't seen the girl drinking and had not witnessed Mays involved in any sexual contact with the girl.

Another witness, a 17-year-old girl, told prosecutors that the girl was unable to lift her head when a now-infamous picture was taken of her being held limply by Richmond and Mays, but she said the girl was not unconscious.

On cross-examination, she told Madison that the girl was able to answer questions and could walk on her own.

The case has cast an unwelcome spotlight on Steubenville, a small, down-on-its-luck town along the banks of the Ohio River.

Critics have accused community leaders of trying to paper over rampant misconduct by players of the highly regarded Steubenville High School football team and have suggested that other students took part in the assaults or failed to do enough stop them.

The case has attracted the attention of bloggers and even the loosely organized hacking group Anonymous, which have questioned everything from the behavior of the football team to the integrity of the investigation.

CNN's Poppy Harlow and Brian Vitagliano contributed to this report.