Luke Donald raced four shots clear of the field at the halfway stage of the Dunlop Phoenix at Phoenix Country Club.
The World Number Three from England followed his opening 65 with a bogey-free 64 to reach 13 under and shake off overnight co-leaders Brendan Jones and Hideto Tanihara.
Donald did most of the damage with a run of five birdies in seven holes from the ninth, establishing a four stroke advantage over Shunsuke Sonoda in the process.
Spain’s Alvaro Quiros went round in 69 to advance to three under and a share of 11th, with his compatriot Gonzalo Fernandez-Castaño two shots further back following a 71.
Ryder Cup star Nicolas Colsaerts also signed for a level par round to remain two under, but 2009 winner Edoardo Molinari missed the cut.
