A college baseball player allegedly ambushed an elderly man in a California bar, knocking the HELL out of him during a drunken altercation that was all caught on video.

Law enforcement sources tell TMZ … Owen Hayes, 21, allegedly got into a heated confrontation with an 84-year-old man inside a Santa Clarita dive bar — and the tensions soon turned violent.

Check out video, obtained by TMZ, which shows the fight that took place in the early morning hours of February 28. It starts with one guy arguing with the geriatric customer, as another man eventually steps between them.

Then the video cuts to a different man — allegedly Hayes — rushing up behind the victim and knocking him to the floor. The older gentleman was reportedly knocked unconscious and hospitalized but fortunately not seriously injured

An employee for the bar tells us the victim is a regular at the Doc’s Inn and said the incident was an unprovoked assault.

Our sources say cops were able to identify Hayes, who surrendered to authorities Monday morning at the Santa Clarita Valley Sheriff’s Station.

Hayes was booked on a charge of felony assault, means likely to produce great bodily injury. He was being held on $50,000 bail.