He really didn't.
He landed basically every single punch he threw until he started to slow down a little bit. His opponent deserves props for being able to take so many clean shots and stay in the fight. Saki did well stopping TD's, but one of the problems with how he did it is that he relied more on his strength to explode out of the position instead of remaining calm and using proper technique to work his way out. Muscling your way out of positions can slow you down very quickly.
Saki is a lifelong kickboxer that had one MMA fight before, but is only now taking MMA more seriously since he has now made the transition. He still has a lot to work on. Overall, his performance wasn't bad at all. He slowed down, but that's what happens when you don't have all the skills like a more experienced MMA fighter to work your way out of a clinch and/or fight off TD's with correct technique, instead using power and explosion to get out.
You, as well as most people here, obviously don't understand that kind of thing though, and since he didn't KO his opponent in 5 seconds, it means his performance was trash. What did his opponent actually do? All he did was get cracked over and over and over and fail TD's and fail to keep Saki in the clinch. Besides one elbow, his opponent didn't do shit and just got beat up and KTFO easily.
He only just transitioned to MMA. He's still lacking in very many important aspects of the game. The majority of other pure kickboxers likely would've been taken down and TKO'd or submitted. Give the guy a break. He's new to this sport and it's going to take him awhile to really get used to how thing work, especially when it comes to conserving energy. Like I said, you and most others don't and probably never will understand that kind of thing.
It's too bad his performance wasn't good enough for you and all the other couch potatoes, though.