Klaasen ever since undergoing wrist surgery in 2017 has fell down the rankings after being one of the most consistent players in the higher echelons of the rankings.
This meant that a first Quarter-Final since 2016 was a shock and he detailed his road to recovery after that run in Minehead.
"Before the tournament started, I think I would have signed for a quarter-final, but I think the way I lost, I was pretty disappointed after the tournament," said Klaasen to the Weekly Dartscast.
"If I hit one of the four darts to be 7-4 in front, and start my own leg for 8-4, I think I would have won that game.
"It's a step in the right direction. I felt comfortable on stage and my wrist is perfect. I'm really happy with my game at the moment. Lately my confidence is growing.
"After I had the surgery on my wrist, for the first year I still had a lot of pain. After one year the pain was gone, but also my confidence.
"I was losing games that I should have never lost, my confidence wasn't there and it took me a long time to get that confidence back. I was playing small tournaments again in Holland to get some wins and to get that feeling that you can beat people again.
"That took a lot of time, almost two-and-a-half years to get my confidence where it needed to be. Last year was the beginning of getting back to the level where I should be - I'm still not there yet but it's slowly getting there."
A week after the UK Open, Klaasen qualified for the German Darts Grand Prix backing up that prowess in Minehead but due to the Coronavirus, it is unsure when these will be played but with him harbouring ranking ambitions, he knows that the European Tour is much needed for him.
"I think the European Tours are the most important tournaments for players outside the top 16 of the world," he said.
"You can make such big steps for the rankings for the Matchplay and World Grand Prix if you qualify for a lot of Euro Tours, so for me it's a massive thing to qualify for one.
"Obviously I wanted to qualify for more but I felt a bit unlucky. This year my goal was to try to get back into the top 32 and you have to qualify for Euro Tours to do that."