A bartender saw a man use a date rape drug. So he swapped the couple's drinks.

After seeing a man spike his date’s drink with a date rape drug, a bartender has admitted to swapping the drinks while no one was looking in a bid to protect the unsuspecting woman.

Admitting to the swap on the anonymous website Whisper, the bartender wrote, “Last night, I saw a guy drug a girl’s drink. When he wasn’t looking, I switched the drinks. Watched that guy drug himself.”

The bartender’s admission was included among 20 other confessions in a thread titled “21 Amazing Moments Where Ordinary People Prevented Sexual Assault.”

Other admissions on the list included witnesses taking police action, physically intervening between aggressors and victims and even a wedding.

"When I was in high school, I saw a guy once slip a roofie at a party to a girl...it was underage drinking, so I left, called the cops... He's still in prison," one person on the thread admitted.

"I stopped a rape at a house party 2 months ago. Me and the girl are now best friends, and the other guy has a wired jaw and a broken nose," another wrote.

"Some guy was sexually harassing a 17-year-old girl at the mall today. I had to fight him away because he was following her everywhere she went. She was in tears and afraid," another said.

"A few years ago, my friend got some girl drunk and started taking advantage of her and I stopped him. Years later, he is no longer my friend and I'm getting married to the girl," one user shared.

Here's to the bartender who hopefully helped teach some important lessons to everyone that night.