It’s crunch time for Filipino challenger Jayson Vayson, who is barely two weeks away from the biggest fight of his life and his career.

While the sparring facet of the buildup is almost done, the next job for Vayson is to go down to 105 pounds next week without sacrificing his physical conditioning.

As defending champion Oscar Collazo of Puerto Rico comfortably trains going into his defense of his twin titles and the Ring magazine belt on 20 September in California, Vayson is devoting a lot of his time watching over his weight.

He hasn’t fought at 105 pounds in seven years and admits he doesn’t know how his body would respond.

Collazo is risking his World Boxing Organization and World Boxing Association minimumweight titles and the Ring strap at the Fantasy Springs Casino and Resort in Indio and is heavily favored to retain his jewels.

But Vayson is willing to do the supreme sacrifice as he attempts to “manage his weight” in the runup to the official weigh-in on the eve of the match.

He arrived in Las Vegas, his training base since 27 August, brimming with confidence in a bold bid to stun one of the world’s best in Collazo, unbeaten in 12 fights with nine knockouts.

“The fight of a lifetime,” Vayson, 27, said during a break in his training at the Knuckleheads Boxing facility owned and operated by Sean Gibbons, the right-hand man of Manny Pacquiao.

Collazo, 28, a hard-hitting southpaw with superb skills, plans to add Vayson to his growing list of Filipino victims after Vic Saludar, Melvin Magramo and Garen Diagan.

To rev up for Collazo, Vayson utilizes stablemate JayR Raquinel, who is actually a lot heavier than him.

Raquinel fights at 115 pounds and Vayson swears his sparmate is quite big, something that might help him get used to the pounding Collazo would bring.