Okay, let me put this in easy-to-understand terms.
Daigo couldn't take a single hit - he couldn't even block one - without losing the match, so he yanked Ken back to a safe distance as a trap for Justin. Justin took the bait and initiated Chun-Li's Super Move, at which point Daigo did a "full parry" (he parried every possible hit of the move) before laying on a counterattack and winning. Daigo's long-storied skill is on full display: he lured Justin into doing the Super, read each frame of the attack, parried each hit as it came in, and counterattacked to win the match. (And since he'd practiced the full parry with sound cues for each hit of the Super Move in mind, knowing he couldn't hear most of them due to the crowd noise makes the feat even more remarkable.) Doing what he did takes skills honed by years of practice, including the ability to read opponents and lay traps for them.
Even at his current age, Daigo remains one of the most experienced, skilled, and all-around respected competitors in the Fighting Game Community. Beating Daigo is like winning a Gym Badge in Pokémon: a hell of a lot of work, but so goddamn satisfying when it happens.