BETHESDA, Md. – A punishing golf course. Temperatures that topped 100. Hunter Mahan still managed to make Friday at Congressional feel like a breeze.

Mahan finally had a good score to match the efficient way he has been swinging the club. He made seven birdies in the stifling heat for a 6-under 65, giving him a two-shot lead going into the weekend at the AT&T National as he goes after a PGA Tour-leading third win of the year.

Chris Couch sought medical attention and struggled to finish in the oppressive conditions. One caddie had to stop after nine holes, and another vomited near the 13th green from drinking too much water.