Nonito Donaire Jr. (second from the left) poses with Julio Cesar Chavez Jr., Wilfredo Vazquez Jr. and Antonio Rubio at the "Welcome to the Future" press conference. Photo by Dyan Castillejo, ABS-CBN News

MANILA, Philippines (UPDATE) – Nonito “The Filipino Flash” Donaire Jr. and Puerto Rico’s Wilfredo Vazquez Jr. nearly came to blows when they engaged in a heated exchange during their pre-fight press conference at the Alamodome in San Antonio, Texas. 

Philboxing’s Ronnie Nathanielsz said the tension began when Vazquez suddenly turned Donaire's cap around during the customary face-off.

This prompted Donaire to retaliate by pulling off Vazquez’s skull cap, triggering a heated verbal exchange and shoving match.

Handlers from both sides immediately stepped in and pulled the fighters apart.

Donaire’s trainer, Robert Garcia, said it was rude for Vazquez to instigate such action.

"You don't do something like that. It's being disrespectful… his grabbing his cap and throwing it away. You don't do something like that to a man and Nonito took it personal,” said Garcia.

He added that Vazquez may be trying to play mental games on Donaire.

“I think he's just trying to make us think that he's ready and he's going to come in and be a monster against Nonito but that doesn't scare us. We're ready," said Garcia.

The trouble actually began early this week when Vazquez’s wife reportedly started a word war against Donaire’s camp through Twitter.

Donaire’s wife, Rachel, said her husband was upset because he treated Vazquez and his father, legendary Puerto Rican boxer Wilfredo Vazquez Sr., with utmost respect.

She said Donaire didn’t expect the younger Vazquez to act rudely.

“When you give that kind of respect you don't expect someone to be so rude and unprofessional. It would be different if it was like the [Vic] Darchinyan fight where all they did was talk back to each other but this fight they weren't even doing anything and they come out taking cheap shots and playing little mind games," said Rachel.

Rachel said Donaire will make Vazquez pay inside the ring.

“They are playing mind games and I don't know what they think it’s going to do. He's just going to go down faster," she said.

The Donaire-Vazquez bout serves as the co-main header of the “Welcome to the Future” fight card, which also features WBO middleweight title clash between Julio Cesar Chavez Jr. and Antonio Rubio.

Welcome to the Future is slated to take place at the Alamodome this Saturday (Sunday in Manila). -- With a report from Dyan Castillejo, ABS-CBN News

ABS-CBN will air the Donaire vs. Vazquez bout on Channel 2 this Sunday at 10:15 a.m.