Udomchoke, ranked 104 in the world, defeated the formidable Lee Hyung Taik of Korea, ranked 49, in two sets: 7-5, 6-3. Japan's Go Seoda and Cecil Mamiit of the Philippines won bronze medals.
Top-seeded Lee, who won men's team gold medal with Korea on 8 December, entered the final as the clear favourite through his world ranking after Srichaphan of Thailand left the tournament with a wrist injury. Lee looked a dead cert, but Udomchoke saved the day.
Lee suffered a setback on Wednesday when he woke up with a fever. He told reporters his condition had improved slightly, but he still didn't have the stamina to match Udomchoke. The Thai is ranked 104th in the world and was seeded third in this event. He took the initiative from the start of the match.
Udomchoke earned his first set point at 5-4 after hitting an excellent volley on a short cross from Lee. The Korean managed to win the game and level at 5-5. Two games later, Udomchoke had two more set points and managed to take the set 7-5.
The confidence boost was all Udomchoke needed and he took control of the second set, dictating most of the points while Lee was constantly defending. Udomchoke broke Lee's serve in the fourth game of the set with a beautiful passing shot down the line.
Lee wasn't able to match the effort and only earned one break point throughout the match - in the third game of the second set - but wasn't able to convert the point.
Udomchoke maintained his effective ground strokes and gave Lee few opportunities to take the initiative, before eventually closing out the set and the match 6-3.
After the game Udomchoke was modest about his success. "I was able to win today, because Lee wasn't playing as well as he usually does. The second set was easier than the first, because he was getting really tired. He might be sick I think.
"We have played so many times before, we know each other well, and we have the same style of play. It was better to play a Korean or Chinese player in the final, because it would have been tough to play an Indian player because of the crowd. I was under a lot more pressure because he [Srichaphan] was not there. I had to make it for Thailand."Â
Lee attributed his loss purely to illness. "I had a fever yesterday. I even thought I might not be able to play today. I lost in the end, but I did my best. This will probably be my last Asian Games and it would have been nice to win the team event and the singles, but it still comforts me to know that at least I won the team gold medal."
15th Asian Games, Doha 2006