The 18-year-old performer managed to complete his set on stage, but passed out briefly in his dressing room afterwards.
The 'Boyfriend' singer said he is "taking it easy" after the incident, reports Contactmusic.
"Just smacked my head and needed some water. All good. I am Canadian. We are tough. It is all good. Just gotta take it easy the rest of the night (sic). Back at it again for you guys tomorrow. Thanks!," tweeted Bieber.
Even though doctors have confirmed that Bieber suffered a concussion, the singer reassured fans that he is fine.
"I will see u again glass. I will have my revenge. Bieber vs glass. MGM Las Vegas 2013. Gotta Laugh At Yourself (sic)," tweeted Bieber.