Kevin Na was cruising along at 10 under par Saturday when he — and caddie Kenny Harms — came briefly unglued at the par-5 11th.

Playing what seemed like a fairly straightforward layup from a fairway bunker, Na's second shot hit the lip and bounded out into the fairway, leaving him 287 yards to the pin.

Trying after his third shot to save his par from the front bunker, Na bladed his fourth over the green and immediately reacted in disgust. CBS announcers suggested a cell phone had gone off during his swing.  Playing his fifth from over the back, he left his chip short of the putting surface and needed two more shots for his double bogey-7.

"Yeah, there was a fan distraction let's call it," Na said after the round. "Kenny being Kenny, he went off on her. He was screaming at her, and he has every right to do so. [But] I felt bad for the lady.

"I was upset at first, and then I saw the lady's face, and I was like, 'Oh, my God. She's going to pee in her pants.' So I said, 'Come on, Kenny. Let's forget about it. Let's just go.'"

Na looked ready to unravel when he sniped his drive into the trees at 12. But he steadied himself with a scrambling par and made up one of his lost shots with a key birdie at 13.

Five more pars and he was in the clubhouse, the leader by two at 9 under.

Na said earlier this week that there's really only "seven or eight" courses on Tour that give him a chance to win. Colonial is certainly one of them. Over the last two years, Na boasts a 66.7 scoring average at the Charles Schwab Challenge. He's the only player in PGA Tour history to have three rounds of 62 or lower at Colonial, and he co-owns the course record of 61.

"It’s a golf course where everyone hits their tee shot in the same spot, whether it’s an iron or a driver," he said. "It’s more of a second-shot-and-in golf course, and I feel like I’m a really good player from the fairway in. My strokes gained: off the tee has never been that great over the years. And that’s just me. I get better as I get closer to the green, and this is a golf course you need to get better as you get closer to the green."