While attending a party with boyfriend Gary Windass (played by Mikey North), Sarah received a call from her brother David (Jack P Shepherd) informing her Bethany (Lucy Fallon) was in danger.
She rushed to Nathan's flat (Chris Harper) where she came face-to-face with the youngster as she emerged from a bedroom.
The school girl could be seen clutching her dress to her chest and holding her shoes in her hand as tears rolled down her face and her mascara was smudged across her face.
Sarah (Tina O'Brien) was visibly shaken as she realised her daughter had been raped by the three men who had left the room before her as she cried: "Oh my baby, what have they done to you?"
Coronation Street: Bethany could be seen clutching her dress in place
Coronation Street: Sarah was crying when she learned the truth about Bethany's boyfriend
My heart just broke for Sarah when she saw Bethany
Coronation Street viewer
Nathan was quickly arrested by police who raided the flat but the teen refused to make a statement and admit that she had been abused by the creepy tanning salon owner.
Those watching at home took to Twitter to comment on the difficult-to-watch scene and praise soap star Lucy for her performance.
"Oh my god. This is heartbreaking. @lufallon you are incredible. #Corrie @itvcorrie," one person commented.
Another added: "I'm in tears right now when Bethany and Sarah came face to face #Corrie."
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Coronation Street: Nathan was arrested but Bethany refused to admit he groomed her Coronation Street's most dramatic moments Fri, June 2, 2017
Coronation Street's most dramatic moments.
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Coronation Street viewers watched in horror as Bethany Platt was sexually exploited by her boyfriend Nathan
Coronation Street: Viewers took to social media to comment on the heartbreaking scenes
A third continued: "Oh my heart just [broke] for Sarah when she saw Bethany #Corrie @itvcorrie @lufallon @tinaob."
"Oh Bethany. Some heart stopping drama in tonight's #Corrie. This is 100% a story that must be told," someone else commented.