OMAHA, Neb. (AP) -- Michael Allen shot a 7-under 63 Friday and broke away from the pack for a 5-stroke lead after the second round of the U.S. Senior Open.
Allen was among seven players who shared the first-round lead at 3-under. He birdied five of the first eight holes and eagled the par-5 14th while shooting his best round of the year in hot, breezy conditions at the par-70 Omaha Country Club.
Allen's 36-hole lead is the largest in the event's 34-year history.
Rocco Mediate, at 5-under, is his closest pursuer. Mediate finished with 14 straight pars while shooting a bogey-free 67. Jeff Sluman, who also shot 67, is at 4-under after missing an 8-foot par putt on the 18th.
Allen was short with his birdie putt on the last hole, ending his bid to match the U.S. Senior Open record of 62 by Loren Roberts at Prairie Dunes in 2006.
The 54-year-old Allen never won in 394 starts on the regular tour, but he has four victories since joining the Champions Tour four years ago, including the 2009 Senior PGA Championship.
He had top-10 finishes in the U.S. Senior Open in 2010-11 and tied for 33rd last year. His game has been on the upswing lately. He won the Mississippi Gulf Resort Classic in March and came to Omaha with three top-10 finishes in his last four events.
It looked as if Allen and Mediate would match birdies early. Mediate had three in four holes to start the afternoon and took a brief lead.
But Allen, playing in the group behind him, got on a tear. He hit every green in regulation while going out in 30 and made the turn with a 3-shot lead.
Allen's strength is his irons, and he was hitting them pure on the front nine, seemingly oblivious to the southerly winds gusting to 25 mph and the course's elevation changes.
The most impressive of his six birdies came on the 477-yard eighth hole, which has been playing as the toughest on the course. He hit a 210-yard 4-iron to 15 feet, then raised his right hand and gave a quick thumbs-up after his straight putt dropped into the cup.
That birdie, however, was trumped a short time later by his round-defining eagle.
The eagle was timely, for it came after he started to struggle a bit. He came up short with a 9-iron into the wind on the downhill, 138-yard 11th. The ball wound up in the bunker in front of the green, but he got up and down with a curling 8-foot putt.
He drove into the right rough on the 12th, chunked his second shot and overcooked his third into the long grass behind the green. He chipped to 6 feet and had to settle for his only bogey.
Allen bounced back with a birdie on the 13th and the eagle on the 14th.
He hit his second shot onto the bottom shelf of the two-tiered 14th green. With his long putter anchored to his chest, there was no threat of Allen coming up short on the 50-foot uphill putt. The ball went up the ridge, hit the back of the cup, popped up and dropped in.
Allen raised his hands, looked to the sky and slapped the fist of playing partner Kohki Idoki before walking to the 15th tee with a 5-shot lead.
Defending champion Roger Chapman was among the players who missed the cut. He followed his first-round 74 with a 76.