This happened on the northwest side of San Antonio in the 2600 block of Vance Jackson.
According to officers at the scene, the woman was visiting a man who lives in an apartment above Beringers BBQ Bar and Grill when the suspect, a man in his 20s barged into the apartment and stabbed her in the neck and three times in the breast.
The apartment resident intervened and the suspect ran off. He was located by police a few blocks from the scene.
Police say the woman, also in her 20s, knows the man but their relationship is unclear at this time.
The victim was taken to University Hospital with possible life-threatening injuries.
Police are investigating.