K.J. Choi watches his drive off of the 14th tee box during the final round of the AT&T National hosted by Tiger Woods at the Congressional Country Club in Potomac, Maryland on July 6, 2008. (UPI Photo/Kevin Dietsch)

Choi shot 3-under-par 67 in Friday's second round making his 36-hole total 1-under 139. He is the only player at the difficult Royal Birkdale golf course with a 36-hole total under par.

Choi's late flurry supplanted club house leader Greg Norman, whose second consecutive even-par 70 earlier in the day made his total 140.

"My expectations for this week were the same as they are now .. realistically low to tell you the truth," Norman said in an interview with ESPN. "I want to keep it that way. I haven't played a lot (and) obviously the last three holes might have shown a little bit of that."

Camilo Villegas (65) is alone in third place at 1-over 141.

First-round co-leader Rocco Mediate (73) is among seven players sharing fourth place at 2-over 142.

Among those missing the cut were Vijay Singh (151), Mark O'Meara (151) and John Daly (169).