Nonito Donaire Sr., the father/former trainer of Nonito Donaire, believes Manny Pacquiao will upset the odds next month by stopping the heavily favored Errol Spence.

Pacquiao will challenge Spence for the IBF, WBC welterweight titles on August 21 at the T-Mobile Arena in Las Vegas.

The eight division champion has been out of the ring since July of 2019, when he won a twelve round split decision over unbeaten Keith Thurman for the WBA title.

Donaire Sr, who also worked as part of Pacquiao's training team at one point, expects a combination of speed and power to overwhelm Spence.

The Elder Donaire helped prepare Pacquiao for his 2018 clash with Lucas Matthysse for the WBA's "regular" title.

He reviewed Spence's fight with Mikey Garcia, who moved up by two weight divisions to take the fight, and felt Garcia was never really hurt in the contest.

Donaire Sr. believes Pacquiao will catch up with Spence in the first half of the fight.

"When he fights a guy with speed and power, we'll see. I think Manny will knock him out in the early rounds. Maybe in the first six rounds, that's the most," Donaire Sr. told

"It's very dangerous for [Spence] because for me when he fought Mikey Garcia, Mikey was way too small for him. He didn't hurt Garcia. I think before Spence can react, Manny can hit him right away because of the speed. Spence doesn't have the speed that Manny has."

This past weekend, Pacquiao arrived in Los Angeles to begin the strong stage of his training camp. He reported on Monday to the Wild Card Boxing Club in Hollywood to begin his work with longtime trainer Freddie Roach and strength and conditioning coach Justin Fortune.

Spence was in action back in December, when he outboxed mandatory challenger Danny Garcia over twelve rounds to retains the belts.