"It's a huge thing. It's sad with the loss of Jerry but also then we can celebrate this here with everybody else as well with the fight night," Vannathy said.
"Every fight, I've been fighting like it's my last anyway so you know you're going to give it everything you've got."
The veteran, who also coaches young fighters and works as a self-employed gib stopper during the day, has a bout lined up in Melbourne later in the year, while he is also mulling offers in Asia. But he knows his days in the fight game - as a competitor - are numbered.
"Life is just getting too busy," the father of three said. "The body's getting older, the recovery's a lot slower."
This week's tournament promises to be a challenging one with a deep field that also includes Wellington fighters Ra Redden (23-6) and Alexi Serepisos (16-8).
South Auckland's Joey Baylon (22-12-3), Hawke's Bay's Pumipi Ngaronoa (30-10), Chris Wells (19-13), Dunedin's Nic Aratema (7-6) and Auckland's Kayne Conlan (15-5-1) round out the field.
"Three in a row would be great," Vannathy said. "I'm in for a tough night at the office.
"I'm always a target when you're the champion. Everybody always wants the king's crown."
Ngaronoa is the WMC New Zealand super lightweight champion, a belt he took from Vannathy over five rounds in New Plymouth last year.
"Winning the King in the Ring means more than the money that's usually up for grabs," Ngaronoa said. "It's knowing that you beat the best in New Zealand on the circuit in one night."
It will be a busy fight night with a handful of other bouts on the undercard, including combat sports code-hopper Gentiane Lupi (14-2) meeting Natalia Teller (10-11-2), while top Kiwi cruiserweight Zane Hopman (18-3) will battle Pati Afoa (28-14-1).