American Brittany Lang upstaged the world's best with a sizzling six-under-par on Friday to take a one-shot lead after the first round of the USLPGA Tour Mizuno Classic golf tournament.

South Korea's Park Hee-Young and Nobuko Kizawa of Japan were in second place in the 1.4-million-dollar tournament after carding 67s, while world number one Lorena Ochoa struggled with a 71 to be tied for 32nd.

Lang, who carded one eagle, five birdies and a bogey on the par-72 Kintetsu Kashikojima Country Club course, said she was elated to have given herself a chance for a maiden tour win.

"I want to have rounds like this, where I don't have many mistakes, and I just keep putting myself in a position to win. It's going to happen sooner or later, so I just have to try to play my best everyday," said Lang.

The world number 33 said she went into the tournament in good form after five top 10 finishes this season that secured her more than 543,000 dollars in prize money.

"I've had a very good year. I've played a lot of really good golf," she said.

Park said she was looking forward to the weekend after a strong finish to her round.

"The birdies on the last two holes built confidence for tomorrow," she said.

Japan's Momoko Ueda, the 2007 champion, was with a group of three other players tied for fourth on 68. Alongside her were Korean pair Song Bo-Bae and Jeon Mi-Jeong, and American Vicky Hurst.

Defending champion and world number two Shin Ji-Yai of South Korea was tied for eighth place with 12 other golfers on 69.

Ochoa said she was disappointed with a slow start to her round and a frustrating day in which her irons were off target.

"I didn't make a birdie until the eighth hole. When you just have two birdies, that's not enough. So I think I need to strike my iron shots a little bit closer tomorrow. Hopefully I will have a better day tomorrow," she said.