Ben Crenshaw and Phil Mickelson couldn't keep pace as a couple of former champions moved into a tie for the lead yesterday at the halfway point of the PGA Tour's Shearson Lehman Brothers Open in San Diego.

Dan Forsman and Steve Pate, each of whom scored his last victory in this tournament, completed 36 holes at 132, 12 strokes under par. Forsman shot 64 yesterday and Pate 65. Each was surprised to be on top.

Forsman, the defending champion, had missed the cut in his last two starts and Pate hasn't won since taking this title in 1988.

Crenshaw, the first-round leader, could do no better than 68 -- and had to drop two 40-foot birdie putts on the last four holes to do that. He fell back into a four-way tie for third at 133.

Mickelson, the 20-year-old left-handed amateur who won the Tucson Open and was a single stroke off the pace after 18 holes here, blew to a 40 on the back nine for 74 and barely qualified for the final two rounds.

Aetna Challenge Seniors: In Naples, Fla., Dale Douglass, unbothered by wind gusts of more than 45 mph, shot a 67 for a four-stroke lead after the opening round.

At 71, 1 under par on the 6,682-yard Vineyards Golf and Country Club course, were Terry Dill, J.C. Snead, Joe Jimenez, George Lanning, Lee Trevino, Don January and Bob Charles.

Quinton Gray, Jimmy Powell, Dave Hill and Harold Henning were at 72.

"In this kind of weather, you don't play golf," January said. "I don't know what you'd call it. . . . It sure wasn't the game I'd normally play. When the wind blows this hard, you stay indoors."