Mark Calcavecchia fired a 6-under 64 on Saturday to grab a share of first place after three rounds of the Senior Players Championship, the third major of the year on the Champions Tour.

Calcavecchia, who won last week's Montreal Championship, moved to 12-under 198 at Fox Chapel Golf Club. He is joined in first place by Joe Daley, who is coming off a tie for fourth at the Senior PGA Championship and shot a 2-under 68 on Saturday.

"The last group's the best place to be," Calcavecchia said during a television interview. "Everybody's in front of you, you know what you need to do."

Defending champion Fred Couples had led at the start of the third round, but slipped into a share of third after managing a round of even-par 70, while battling a sore back.

"My back's killing me," Couples said in a TV interview. "I just really couldn't hit the ball."

Couples stayed at minus-11 and shares third with Tradition winner Tom Lehman, who carded a 4-under 66.

Jeff Freeman used a 5-under 65 to climb into fifth by himself at 10-under, while Fred Funk's 64 got him into sixth at minus-9.

Couples had fired a 63 on Friday to put himself on pace for a second consecutive title at this event, but never got any momentum going Saturday because of his back.

He birdied the second before giving the stroke away at the fourth. A birdie at 10 got him back to 12-under, but the lead soon changed hands.

Daley made the turn at minus-10 after rebounding from a rough start. He stumbled to bogeys at Nos. 3 and 4, but birdied two of his next three holes. Like Couples, he birdied the 10th, but to reach minus-11.

Meanwhile, Calcavecchia was playing a group ahead of Couples and Daley, and set himself up to challenge for the lead after carding three birdies on his front nine. He then birdied the 11th to reach minus-10, and was within two strokes of Couples.

But on the 14th hole, Couples stumbled to a bogey as Daley made birdie to take the lead. Meanwhile, Calcavecchia was ahead at the 15th and birdied that hole.

After that stretch, Daley was in first place at minus-12, with Couples and Calcavecchia a shot behind. Couples fell another stroke back after a bogey at 15.

Calcavecchia got a piece of the lead after rolling in a birdie at the last, while Daley parred out to stay at minus-12. Couples partly made up for his earlier mistakes with a birdie at the par-5 18th.

Heading into Sunday, Daley will be trying for his first win since the 2005 Wichita Open, a Web.com Tour event. He never won on the PGA Tour and hasn't titled in a Champions tournament.

The 51-year-old will certainly have his work cut out for him, considering the quality of his competition. Calcavecchia and Couples both earned more than a dozen PGA victories and are major champions -- Calcavecchia at the 1989 British Open, and Couples at the 1992 Masters. Lehman is the 1996 British Open champion and has earned three major titles on the Champions Tour.

NOTES: Kenny Perry aced the par-3 17th during his round of 3-under 67. He is tied for eighth at minus-6...D.A. Weibring withdrew Saturday.