Fred Funk eagled the last to set a record 11 under par halfway total at The Senior Open Championship presented by MasterCard and take a seven shot clubhouse lead.
The 53 year old American, whose opening round 64 was also a tournament best, recorded a two at the 423 yard 18th after he sunk a 168 yard eight iron.
That capped a flawless round as the fomer Ryder Cup star shot three birdies without dropping a stroke for the second day running.
“I don't feel like I shot 65,” said Funk. “It's just the way it all added up at the end. When you do what I did at the finish and then all of a sudden you're five under par, you go, wow, where did that come from?
“It wasn't like I walked off thinking I shot this great round, although it was a round I would have loved to have before I teed off, that's for sure. I birdied 16 and holed a shot on 18 and all of a sudden it looks like a great round that I played,” said Funk – who reached halfway on 129 for the second time in three rounds, although at The Dick’s Sporting Goods Open last month he could only go on to tie for second.
“There's a lot of golf to be played, but yeah, I'm playing well. If I keep doing what I'm doing and especially putt as well as I've been putting, it will be hard to catch.”
Funk’s 65 for an 11 under total looked increasingly hard to catch as the rest of the early starters in Sunningdale struggled to break par.
Second in the clubhouse was Zimbabwe's Denis Watson, who shot a second successive 68, and Ireland's Mark McNulty but at four under they were both going to have their work cut out trying to catch Funk this weekend.
Those set to play this afternoon were delayed when play was suspended due to a thunder storm shortly before 2pm, although play resumed at 3.40.
Loren Roberts, the 2006 winner of this event at Turnberry, advanced to six under through seven holes to emerge as Funk’s main challenger.
Scotland’s Sam Torrance, who lives nearby and knows Sunningdale’s old course as well as anybody in the field, birdied the third and fourth to move into sole possession of third place. After a gutsy par putt at the seventh Torrance looked in trouble at the next when his tee shot found the large greenside bunker but he splashed out to six feet and again held his nerve.