David Peoples, Michael Allen and Mark round lead after shooting matching six-under 66s on Friday at the Songdo Championship Korea.
Calcavecchia is looking to build off his first Champions Tour win at the Boeing Classic in August. He got into the clubhouse Friday tied for the lead after a final birdie on No. 18, totaling eight birdies and two bogeys at Jack Nicklaus Golf Club Korea.
He'll be in the final grouping in Saturday's second round, a place Calcavecchia certainly doesn't mind being.
"It's always fun to be in the last group and tied for the lead," he said in a televised interview. "Every week you get to play with guys you played with the last 25 to 30 years."
He'll play alongside Allen, who is looking for his first senior win since coming away victorious in his inaugural Champions Tour event at the 2009 Senior PGA Championship. He's had three runner-up finishes since, but no wins.
"It would be nice (to win). It's been a long time since I won," Allen said on TV. "I kind of expect to win more lately."
Peoples, meanwhile, is still seeking his first win since capturing the 1992 Anheuser-Busch Golf Classic. He had an eagle, five birdies and a bogey on Friday.
"I hit the ball really good. I drove it in the fairway most of the time," People said in a televised interview. "I got a few good breaks around the greens. A few putts went in. There were a lot of opportunities, and some of them fell."
The three aren't the only ones in contention, as Mark O'Meara came in only a stroke behind at five-under 67. Jay Don Blake, Tom Purtzer, Tommy Armour III, Peter Senior, Tom Pernice, Jr. and John Cook lurk two shots back at minus- four.
Calcavecchia began on the first tee and got off to a fast start with three straight birdies from the second. He stumbled to bogeys at six and eight, but was flawless from that point forward.
He birdied the ninth to make the turn at two-under and got to three-under with a birdie at the 11th. Calcavecchia birdied the 14th and 15th before a closing birdie at the par-five 18th gained him a share of the lead.
Peoples also began from the first tee and birdied two straight from the third. His lone bogey came at the sixth, and he played a remarkable back nine to move atop the leaderboard.
Over the final nine holes, Peoples recorded an eagle at the 15th and birdies at 11, 13 and 18 to get to six-under.
Allen began on the back nine and posted birdies at 15 and 18, then began the final nine holes in style with birdies at the first and second and an eagle at the third. He bogeyed the seventh, but a final birdie on No. 9 put him at six- under.
Defending champion Russ Cochran has a share of 11th at three-under 69.