By Andrea Swalec, Tuan Nguyen and Tom Liddy
Kasey Beyer, 27, and her husband Kasey Beyer, of Iowa, came all the way to New York to see Bieber perform.
"Yeah, [we came] all the way just for his show," said Kasey Beyer, a kindergarten teacher.
The Canadian pop prince tickled the ivories and belted out "Let it Be" around 10 p.m., which was followed by a massive cheer.
"He was beautiful and wonderful," said Daysi Grullon, 22, of the Lower East Side, who came to the party with her friend Ashlen Rivera, 21. "I wish he had sung a song I knew.
"We've liked him since he first came out."
As for Rivera, she thought Bieber "was very sexy."
For Kati and Kiki Culp, sisters from Leesburg, Va., it was all about the Bieb's piano playing and trying to get Lady Gaga's autograph.
"It was cool because he played the piano," said Katie, 8.
"We're going to try to get her autograph" said Kiki, 6, of Gaga. "They're both very talented."
Lady Gaga, donning a black costume with sparkles and a globe-shaped cage around her around her head, took the stage just after 11:30 p.m. and performed "Marry the Night" and "Born This Way."
"She was so good. I loved the part when she climbed onto the poles. No one else did that," said Avery Reiter, 13.
"She looked so happy while she sang."
But others missed out on their chance to see the big show.
"My wife and two sisters are crying in their hotel," said Max Becker, 52, of Mexico, as he had dinner with his son and brother in a deli on 44th st. "They got to the square at 3 p.m. but after two hours they left."
"They said, 'Too crowded, so many people and they stood too close,''' he added. "We came all the way here for it and they were so upset now. They came for Bieber boy and Lady Gaga."