In the process, Thelen ensured that he will finish in the top four of the 2012 Senior Tour Order of Merit and has therefore earned a place in next year’s US Senior Open Championship.
The man from Texas, who has become the first American to claim three Senior Tour titles in one season since John Grace in 2000, started steadily with pars at the first six holes and by the time he reached the seventh tee, Thelen had made up the three shot overnight deficit as Kim bogeyed the third, fifth and sixth.
Suddenly, the 51 year old was five shots clear and not even his first bogey of the tournament at the ninth hole, after finding water, could halt him in his path as he sank a superb 18 foot putt at the 13th to card another birdie and put one hand firmly on the trophy.
“It’s unbelievable,” said Thelen. “Words cannot describe how incredible this is for me. I had been a playing pro for 23 years and I was just delighted to get on the Senior Tour last year but to win three times this year is just unfathomable.
“I played really well all three days out here and the wind blew hard today and when it rained, it rained really heavily but I hung in there and thankfully I came out with the win.”
Former Senior Tour Order of Merit winner Boonchu Ruangkit finished in fourth place on eight under par while the best of the Taiwanese was Chi Hsiang Lin, who carded a final round 75 to finish in tenth place on four under par.
A former college mate of Colin Montgomerie at Houston Baptist University, Thelen won Qualifying School by five shots in 2010 to gain an exemption for the 2011 campaign and he retained that card thanks to a 24th place finish in the Order of Merit that year.
But this year his career has been launched to a whole new stratosphere, as the two-time National PGA Club Professional Championship winner claimed his maiden Senior Tour title at the Berenberg Bank Masters before following that up immediately with a second win at the Bad Ragaz PGA Seniors Open the following week.