A few hours before the pre-combat weighing at Madison Square Garden, fans started gathering.
While the fans took their seats, there were many Irish flags in the show.
Boxer promoter Eddie Hearn told me to expect thousands of Irish fans to fight, so it's no surprise that many of them came to see Katie Taylor on pre-combat weighing.
The fans I spoke to have traveled from various parts of Ireland, some say that they already live in the United States and they all had one common thing: a firm conviction that they would win Katie Taylor.
One of the biggest winds of the night came when the Bray boxer went over to the scale.
If he defeats Belgian Delfin Persoon, she will become the undisputed world champion.
Hearn described it as an absolute gold cup for any fighter.
"For Katie Taylor, this is probably the greatest moment in her life, and I'm nervous and excited about her," he said.
Katie's mother Bridget was also weighing. She said it would be a tough fight, but she was quietly convinced.
"It would be really a big boxer to win Katie," she said.
Katie's manager Brian Peters described it as a struggle for her life.
"She has the opportunity to join a very elite group of people and create history," he said.