A dozen teams are battling in this exhibition event, hosted by Greg Norman at the Tiburon Golf Club.
A different format is used for each of the three rounds and Friday's format was a modified alternate shot, in which both players hit a tee ball. The best shot is selected and then the players take turns striking the ball until it is holed.
The pairings of Harris English-Matt Kuchar and Charles Howell III-Justin Leonard also shot a 64. Two-time U.S. Open champion Retief Goosen and Freddie Jacobson turned in a 67 to stand alone in fourth place while a 68 was fired by the teams of Jason Dufner-Dustin Johnson and Chris DiMarco-Billy Horschel.
Friday's format normally produces the highest scores of the week. The players compete in the better ball format on Saturday and in a scramble on Sunday. Both the final two rounds could produce scores in the 50s.