As recounted by USA Today and in graphic glory on YouTube, Stratford, Ontario’s Justin Bieber had a mission with his new Believe tour, which kicked off Saturday at 18,000-seat Jobing Arena in this Phoenix suburb. It was to show that the 18-year-old was ready to eclipse the tween YouTube phenomenon and prove he was an entertainer of merit and endurance. … In an impressive embodiment of show-must-go-on bravura, Bieber succumbed to an upset stomach not once but twice during his 21-song set, leaving fans wide-eyed and concerned, only to then charge back on stage.

Bieber then powered through his Karate Kid theme song, Never Say Never. But a few thumps into Beauty and a Beat, his duet with Nicki Minaj (who provided her rap via a taped performance on a central video screen), the lanky singer vanished again, this time resulting in a complete halt to the show for a few minutes.

When he finally returned, Bieber had the poise and innate show-business smarts to come clean with the audience. “It’s hard for me, you know, not feeling great and throwing up in front of a bunch of people,” he said to laughs. “Will you love me even though I’m throwing up on stage?” Shrill shrieks. “OK, I wanted to give you my best show ever, so do you mind if I finish it?”