TMZ.com said the National, an English language newspaper in Abu Dhabi, reported Bieber was at the piano when the incident occurred. The fan was taken away by security and Bieber went on with the show.
Earlier, Bieber was two hours late for his first performance ever in the United Arab Emirates, officials said.
Bieber performed in front of a crowd of at least 27,000 fans inside Dubai's Sevens Stadium Saturday, Gulf News reported.
The 19-year-old Canadian idol showed up to the sold-out show about two hours late, organizer Done Events said. Although some in the crowd started booing at some point, most stuck it out and waited patiently for Bieber.
"Recent shows on this tour have started late and so the artist was also later than scheduled in taking to the stage last night. We really empathize with the fans and their parents who were affected by the delay and to whom this might have caused some inconvenience. We know that many parents had to look after tired and exhausted children both at the stadium and I am sure this morning, as they try to get them up for school," Thomas Ovesen, chief operating officer at Done Events, said.
"All that said the fans who saw Justin in action loved the incredible show he put on and they left screaming with delight as chants for the superstar echoed around the stadium. With the final night of his tour here in Dubai happening tonight, we are still very much expecting the artist to start the show at 8 p.m. as scheduled but urge fans again to come well prepared if the show time again is moved a little," Ovesen said.