On day one at the Memorial Tournament, Jason Dufner was just about perfect through 17 holes. He was at eight-under, alone in the lead, and had yet to make a bogey. His approach into the difficult green on the 484-yard par-4 18th hole found a greenside bunker, and he ended up settling for his only dropped stroke of the day for a seven-under 65.

Halfway through Friday’s second round Dufner once again hadn’t made a bogey, and walked to the 18th tee (his ninth hole) at two-under on the day, nine-under for the tournament. Surely, he would just take his par and run this time. Not quite.

The 175-yard hole-out resulted in a four-under 32 on the front nine, getting him to 11-under for the tournament. He’s followed it up with four straight pars and three consecutive birdies, putting him at 14-under and five shots clear of the field.

Through 36 holes the 2013 US PGA Champion has just one bogey, two eagles, and 11 birdies. Dufner, 40, has flown under the radar this season, making 12 of 14 cuts and finishing in the top-25 nine times. He’s looking for the fifth win of his career this week, and his first since last season’s CareerBuilder Challenge.