Johnson changes putters to take Shanghai lead

World number one Dustin Johnson tees off during the second round of the WGC-HSBC Champions at the Sheshan International golf club in Shanghai. - AFP

Shanghai (AFP) - Dustin Johnson switched putters at the last moment and then nailed four birdies in his last four holes to seize a one-shot lead at the halfway stage of the $9.75 million WGC-HSBC Champions in Shanghai on Friday.

The world number one's spectacular nine-under-par 63 catapulted him over fellow American and overnight leader -- and good friend -- Brooks Koepka, who hung on for second on 132 overall.