The South Korean bogeyed the fourth , however , to double the American 's advantage at the top .
Chun was unable to get any closer once Thompson had moved further clear with an eagle on the par - five 10th .
The South Korean bogeyed the fourth , however , to double the American 's advantage at the top and Chun was unable to get any closer once Thompson had moved further clear with an eagle on the par - five 10th .