Colin Montgomerie continued to roll back the years as he moved clear at the top for the US Senior Open leaderboard in Oklahoma.
Montgomerie, who won the Senior PGA Championship in Michigan, twice sank three consecutive birdies at Oak Tree National as he finished with a six-under 65, one shot clear of Marco Dawson.
Montgomerie, who started his round on the back nine, birdied the 14th, 15th and 16th before picking up shots at the sixth, seventh and eighth.
"I was patient, I was relaxed," Montgomerie said. "We had a good time. I was happy with the pairing we had, the three who were playing together.
"We played a lot together over the first year of my Champions Tour life. But the statistics, you know, add up. Sixteen greens out of 18 (in regulation). Not bad statistics, really.
“And then 11 fairways out of 14. You'd take that. So, yeah, just a good run of golf. A good, solid round of golf today."
A trio of birdies were also key to Dawson’s challenge, with picked up shots at the seventh, eighth and ninth helping him to five-under after he had started his round on the 10th.
"It just seemed to happen; birdie, birdie, birdie the last three holes, so I ended up five-under," he said. "I could have shot 2 under and still would have been a good round."
Mark Brooks was back in third after shooting 68, while Bernhard Langer, Kirk Triplett, Scott Dunlap, Gene Sauers and Vijay Singh were tied for fourth with a 69.
Defending champion Kenny Parry struggled, though, as he shot a four-over 71.