With 15 minutes until chef-owner Chris Bianco opened the doors, only a dozen or so people had gathered outside his Pizzeria Bianco on East Congress Street Thursday afternoon.

For a moment, it looked as if the 107-degree heat baking the concrete would rob Bianco of his much-anticipated opening night frenzy.

But it took only 10 minutes before 45 people had streamed through the front door. By 4:30, the dining room was full and the bar overflowed with Tucsonans curious to sample what has long been billed as the best pizza in the United States.

“This is surreal,” said Pizzeria Bianco Chief Operating Officer Seth Sulka as he snapped photographs of diners streaming in.

Judging from the chorus of oohs and aahs, the opening was a hit.

“Oh my gosh,” gushed Rita Ranch resident Tyler Murray as a server set a fresh-from-the-oven Rosa pizza before him. “It has onions and pistachios. Oh my. It’s much bigger than I thought.”

“We would pass by and say, ‘Open, open, please open,’” said his dining partner Larry Eberle, who was tucking into a Sonny Boy topped with olives and salami. “I’ve had pizza in Bologna, Italy, but when it comes to pizza, Bologna can’t hold a candle to Tucson. It’s delicious.”

Thursday’s opening initially was meant to be an invitation-only event. But Bianco decided to serve at no charge whoever walked in the door, including die-hard Pizzeria Bianco fans Weldon Ferrell, Mike Jaret and Vince Desi. The trio, regulars to Bianco’s flagship pizzeria in downtown Phoenix, were among the first people to arrive just after 3:30 p.m.

“This is the only place that I have ever waited in line for,” Ferrell said, recalling times that he waited for up to four hours to get into the Phoenix restaurant.

“If you are a pizza purist, this is where you go,” added Desi. “Bianco is a pizza purist.”

Thursday’s opening came more than year after Bianco announced in April 2013 that he planned to open Pizzeria Bianco downtown. Initially, he wanted to open late last year, but the plans took a backseat to Bianco’s life, which included getting married, opening a London pizzeria with celebrity chef Jamie Oliver, and welcoming daughter Nina Rose in April.

This is Bianco’s fourth restaurant, but the only one modeled after the original Pizzeria Bianco, which he opened in downtown Phoenix in 1994.

In 2003, Bianco won a James Beard Award — the only pizza chef ever to win the prestigious award.

Since then, he has been showered with praise from The New York Times, Vogue magazine, Bon Appétit, Food & Wine and USA Today, as well as celebrity endorsements from Oprah Winfrey, Jimmy Kimmel, Diane Sawyer and former President Bill Clinton.

I cover music for the Arizona Daily Star.