"Today I wasn't at my best physically and I think I should be given only 5.5 out of ten," the Manchester United star told reporters after the game.
The appearance was Park's first for the national team since March 2007 and the last goal he scored was against France at the 2006 World Cup.
"Even when I return to England, the goal can have a positive effect for me," Park added.
The former PSV star believes that there is much work to do for South Korea.
"Turkmenistan gave us few problems. You could say that our problem was that we didn't score quickly but after our first goal we kept scoring.
"As we haven't spent much time training together, we didn't combine as a team as well as we could have. If we keep working hard in training then even against strong teams we can play well."