Justin Bieber pays tribute to Avalanna in AZ

UNDATED (WHDH) -- It seemed "the Bieb" himself came down with a case of "Bieber fever."

The teen idol kicked off his national tour this weekend in Phoenix and an upset stomach wasn't going to stop him.

Bieber vomited twice on stage Saturday night in Arizona.

He left the stage after each episode but returned to the stage and even performed an encore.

At the show, he also paid tribute to "Mrs. Bieber," Avalanna Routh, who lost her battle with cancer last week.

Bieber sang "One Less Lonely Girl" as a video montage of Avalanna and her family and photos of her February "date" with Bieber played.

Bieber usually pulls a girl from the crowd to serenade but Saturday night he said he was singing the song to Avalanna.