BLAINE, Minn. -- Tommy Armour III was the first player off the tee Friday. He'll be the last one off Saturday.
"Every day is a good day to shoot 63, but it's a 54-hole tournament," said Armour, who shot a 61 at The ACE Group Classic in February and a 63 at the Principal Charity Classic two months ago.
On a perfect day for golf -- temperatures in the low-80s, partly cloudy skies and little wind -- 45 of the 78 players finished under par.
"The course was there for the taking today," Calcavecchia said. "The greens were soft."
Armour, who had two victories in more than 20 years on the PGA Tour, has three second-place finishes in 12 previous starts during his rookie year on the Champions Tour. He was disappointed with his play the last two weeks, yet finished eighth at the Senior British Open and 11th at the U.S. Senior Open. His eight combined rounds in the tournaments ranged from 68-74.
"Out here you've got to play good every day," he said.
Calcavecchia said that is especially true this week. The last three 3M Championship winners have finished between 16- and 23-under par.
"Unless the wind starts blowing like it did yesterday afternoon, 20-25 mph, and we get two more nice days, I've got to believe you're going to have to get close to 20-under par to win," he said. "That's a lot under par for three days, I don't care what tour you're on. The hole's the same size. That's pretty good golf."
The weekend forecast calls for hot and humid conditions with winds of no more than 10 mph.
Starting on the back side, Armour birdied three of his first four holes and added another at No. 18. Birdies on Nos. 2 and 3 got him to 6-under par, before he birdied his last three holes. Armour, who ranks 10th in tour putting average, one-putted for seven of his birdies.
"The Champions Tour is a momentum tour," he said. "Tomorrow you got to start on the first hole and get after it, because if you don't, somebody will."
Calcavecchia, who also started on No. 10, was 2-under at the turn before finding his rhythm.
He birdied No. 2 from about 5 feet and eagled the par-5 third with a 15-foot putt. He also eagled the par-5 sixth by chipping in from a greenside bunker.
"It feels good. I hit a lot of good shots, made a lot of putts and a good bunker shot," he said.
Playing in a group with Calcavecchia, Frost was 3 under at the turn, before four straight birdies on the front side. Frost, who switched back to his old putter before the round, made a 40-foot putt at No. 8 to get to 8 under.
"I made some good putts at times. I could have been one shot better or one shot worse," said Frost, who has five top-10s in 14 events in his first full year on tour. "Putting is always the name of the game."
His putting was especially accurate on the four par-3s. He birdied each of them -- two from about 8 feet, one from 30 feet and another from about 40 feet. He also lipped out an eagle putt on the third hole.
Defending champion Bernhard Langer -- the winner of senior major tournaments the last two weeks -- is one of nine players that are five shots back. No champion has defended his title in the event's 18-year history.