UPDATE 1-Golf-Kerr leads Creamer by one at U.S. Women's Open

* Kerr shoots 70 for three-under-par total

* Creamer sinks 35-foot birdie putt at the last for 68 (adds details, quotes)

By Larry Fine

BETHLEHEM, Pennsylvania, July 10 (Reuters) - Cristie Kerr shot a one-under-par 70 on Friday to take a one-stroke lead over fellow-American Paula Creamer at the halfway mark of the U.S. Women's Open at Saucon Valley's Old Course.

Kerr, the 2007 champion, stood at three-under-par 139, while Creamer drained a 35-footer to birdie the last and finish with a 68 for 140.

Another stroke back was unheralded American Jean Reynolds. The 24-year-old Futures Tour player shot 72.

"I played great," said 31-year-old Kerr, who has three other top-10 showings in the championship besides her victory.

"The mindset for the weekend is you have to be focused on every shot and you got to be paying attention on every shot."

Tied for fourth on level-par 142 were first-round leader Choi Na-yeon of South Korea, who posted 74, and Giulia Sergas of Italy, who fired a tournament low 67 despite bogeying the 18th.