Choi's round began with a run of four consecutive birdies

R2 LEADERBOARD:
US unless stated
-8 K J Choi (Kor) Gay
-7 E Els (SA), B Gay, J Byrd
-6 P Goydos
Selected others:
-2 V Singh (Fij)
-1 M Weir (Can)
Level J Rose (GB), B Langer(Ger) J Leonard
+1 J Parnevik (Swe), F Funk
+3 A Scott (Aus), R Goosen (SA)

KJ Choi holds a one-shot lead after two rounds at the Chrysler Championship with a five-under-par 66 on Friday.

The South Korean is eight under for the tournament, one ahead of Ernie Els, Brian Gay and Jonathan Byrd.

Choi's advantage could have been even bigger after opening with four birdies, but a double-bogey at the eighth hole cost him his error-free round.

Vijay Singh lies six off the lead on two under but both Adam Scott and Retief Goosen failed to make the cut.