Emma Capper, aged 37, forced her way into a flat on Victoria Street where her victim was visiting friends at around 9pm on December 9 last year.
Detective Constable Helen Critchley, who led the investigation for South Yorkshire Police, said: “Capper knew her victim was at the address that day when she barged her way in and launched a brutal assault, hitting her victim in the face, slashing her with a penknife and leaving a huge wound on the side of her head.
"The victim's friends watched horrified as they raised the alarm with the building’s security guard and called an ambulance.”
Capper was identified on CCTV and was arrested several days later by officers after extensive enquiries.
DC Critchley added: "Capper was known to her victim through mutual friends, but there was no apparent catalyst for the attack that night. In police interviews, Capper accused her victim of stealing her phone and claimed that her victim had started the fight.
“Evidence from witnesses and our enquiries did not support these claims and Capper was charged with wounding with intent and remanded into custody.”
Capper, who gave her address as the Staindrop Lodge Hotel, Sheffield, pleaded guilty at a hearing on January 13 and was sentenced to seven years in prison at Sheffield Crown Court on Friday, March 5.
DC Critchley said: “Capper is a violent and nasty individual who left her victim with significant facial injuries that night. I hope this substantial custodial sentence is reassuring to the victim and the wider community."