Nonito Donaire is confident his countryman Manny Pacquiao can do the job on Errol Spence Jr when they finally face each other in a unification showdown this summer. 

The legendary Pac Man, 42, who was originally supposed to be facing Terence Crawford before talks broke down, will finally get his shot on August 21, when he will get the chance to add another world title to his growing collection in the form of Spence Jr's WBC and IBF welterweight titles. 

Spence Jr (27-0, 21 KO's) is currently unbeaten, while Pacquiao's most recent loss came against Jeff Horn in July 2017, which has prompted some to write him off almost immediately. 

However, four-weight world champion Donaire, who is coming off a win over Nordine Oubaali last Saturday night, has refused to dismiss his chances against Spence Jr. 

Like his compatriot, 'The Filipino Flash' feels that age is just a number, and has given his full backing to his fellow countryman to shock the American at the MGM Grand Garden Arena in Las Vegas, Nevada.

"He's just like me, you know. He's just a little bit older," Donaire said to FightHype.com. "You can't underestimate the guys who have been there and who have done it.

"Of course, it depends on their mentality and their training habits, or how hard they're training, but a champion will always be a champion."

"Regardless if they don't show it one day, they might show it the next, you know, and he might show it with Errol Spence Jr," he added.

"So, you just can't underestimate guys like that, like Manny, he still has power, he still has the knowledge for it.

"But that's the thing about boxing, you never know until it's done."

He continued: "I know that Manny has the capability. Errol, he has his own ups and downs, you know, being in an accident, did that affect him, this and this and that. 

"You know, there's a lot of things that are up in question. 

"But I mean he is one of the young guys who are [sic] one of the best fighter right now against the guy who has been there, who has done it, and I believe that he still has it. I think it's going to be a competitive fight." 

Pacquiao will be well aware of the scale of the task that lies ahead, having fought just once in the last two years, in July in 2019, defeating Keith Thurman via a close split decision. 

Spence Jr, meanwhile, seems to have shaken off the lingering after-effects of the car crash he suffered in October 2019, beating Danny Garcia by unanimous decision in December of last year, following his highly impressive points win over Shawn Porter.  

Read more: Manny Pacquiao vs Errol Spence Jr: Ricky Hatton fires warning