Dustin Johnson takes halfway lead at Sheshan International in Malaysia . Shoots course record equaling 63 at HSBC Champions . First round leader Rory McIlroy falls back into tie for second . ` But I 've had too many mistakes , '' he admitted . Americans Open champion Dustin Johnson seven shots adrift .
Dustin Johnson takes halfway lead at Sheshan International in Malaysia . Shoots course record equaling 63 at HSBC Champions . First round leader Rory McIlroy falls back into tie for second . Americans Open champion Dustin Johnson seven shots adrift .