The Japanese player began the week at Woo Jeong Hills Country Club in 106th on the Race to Dubai Rankings delivered by DP World, with the top 100 after the event earning their playing rights for next season.
However, Katsuragawa blitzed the field on Moving Day as he matched the course record of 63 to open up a two-shot advantage heading into final round.
He could not get his Sunday going as he carded just one birdie, at the fourth, but minimised blots on his scorecard with 16 pars before a closing bogey for a total of -13.
It mattered not as he earned a two-shot victory over French duo Frederic Lacroix and Martin Couvra both -11, who sealed their places in the playoffs with a T2.
"After the first win, I had such a hard time, struggling with that time, but having the second win, this is definitely the greatest moment of my life," Katsuragawa, who has also sealed his spot in both playoff events, said.
"Yes I was nervous, not just for the victory but also about the seed for the DP World Tour so it was double nervous for me but I think I got through.
"I had a good image from the first victory, I just kept that good feeling about it and I came for the second win.
"I'm very happy because to play on the DP World Tour is something I need in my life and I am very happy to play in Dubai."
Pressure ramped up on Katsuragawa when he got out of position with his first and third shots at the last, he had three putts for victory and he celebrated his first crown in over two years after tapping in the second for bogey.
Open Champion Ryan Fox was joined at -10 by Rozner, Jarvis, Italian Filippo Celli, Spain's Jorge Campillo and home duo Sanghun Shin and Si Woo Kim for a T4.
NUMBER 100
At the other end of the field American Sean Crocker gave us all the emotional full picture of what life on the DP World Tour can be like when you are struggling to keep your card.
He has shot 72 71 69 68 -4 to claim the last spot at #100 and get his full playing rights for 2027.
"That was probably one of the better back nines I've ever played with circumstances and everything going on there, it was pretty good.
"Those final two tee-shots on 17 and 18 were as big as I could hit it and then that putt on 17 was massive and then to just chip it to give on 18 so I didn't have to think about it was really nice."
When asked what he thought at the turn, Crocker said: "I'm not going to Q-School! If I'm being dead serious. I don't really know how the new categories are working and stuff like that, but that's 12 weeks on the trot, I've not seen my wife and child for a handful of weeks now I knew it would be a week off and then Q-School if that was the choice I made.
"I just really wanted to give it every chance I could to be able to spend a little time at home to be a dad and a husband, because it's been a while and I miss the living hell out of them.
He added: "It's not easy being a Tour player, being away from your family especially when you are on the bubble and obviously I'm not the only person, but the last thing you want to do is start a little family and get demoted or lose some of your playing rights so I was obviously thinking about his (son, Cruz) future and making sure my wife never has to have a job I guess.
"It was definitely on the back of my mind that I also have Stevie (Pettit, caddie) to take care of, there's lots of things that weigh on our shoulders when we are out there playing golf and I was just trying my ass off to get it in."
europeantour.com
Bryan Angus (edit)
