Gil Morgan, a 43-year-old optometrist called "Doc" who was winless on the PGA Tour for seven years, sank a four-foot par putt in a thunderstorm on the 18th hole at TPC at Avenel to defeat Ian Baker-Finch by one stroke in the Kemper Open yesterday.

Morgan, with lowering black clouds pursuing him, arrived safely indoors at 10-under-par 274. He became the tournament's oldest champion with a neat chip and unwavering putt that came several minutes after the clouds burst open. Nearly an hour earlier, Baker-Finch was unable to negotiate a similar up-and-down there and dropped to nine under.

There were four leaders and numerous contenders over the final round on the par-71, 6,917-yard layout. Morgan's closing 69 was not the lowest score or the most elegant, a ragged journey of four bogeys and six birdies. But he labored safely home over the wind-plagued final three holes -- something 29-year-old Baker-Finch could not do -- to earn $180,000. Baker-Finch received $108,000 for his travail.

Morgan was hardly a favorite as he began the day, aging and all but forgotten after undergoing career-threatening surgery for a torn rotator cuff in 1986. His hadn't won since the 1983 Los Angeles Open. But he prevailed over an array of contenders that included two-time U.S. Open champion Hale Irwin and 1989 Masters runner-up Scott Hoch. They tied for third at eight under par.

"It feels great, to tell you the truth," Morgan said. "Obviously you question your ability to win again. At some point you know it's going to be over. You just don't know when."

Baker-Finch surged from seven strokes back, and for a while seemed certain to win. But the Australian made a fatal bogey from a deep bunker on the 18th, catching his blast from the sand on the lip and leaving it in the short grass. He had begun the day four under, and took refuge in the CBS-TV tower to watch the others finish.

"I still thought it would be all right," he said.

All began the day trailing Steve Jones by at least three strokes. He had made a hole-in-one on the par-3 ninth on Saturday, and yesterday started with a birdie to move to 12 under. But Jones suddenly and horribly disintegrated with a double bogey at the ninth en route to a 78.

"It was tough," he said. "You just have to learn from it."

That threw the door open to all comers, in what was a memorably competitive final round. Avenel, with its tree- and creek-lined design, was moody in cool, swirling wind of 20 mph and a constant threat of rain. The wind made a number of holes unreadable, and Baker-Finch's 66 was as low as was shot all day.

That Morgan was not a factor on the early holes was a lesson in how quickly a final round can change -- and also in how long it can take, this one an epic 4 1/2 hours. His front nine was a zigzag of three birdies to three bogeys, including a shot that clipped a tree branch and fell into the creek at the par-5 sixth hole. He did not take the lead until he sank a last birdie putt at the 15th.

"I got off to a real erratic start," he said. "My consistency wasn't very good. I thought I'd never get anywhere with that method."

Hoch briefly was the leader at 10 under through 10 holes, but was erratic all day and had to struggle for his round of even par. He relinquished the lead when he double-bogeyed the creek-bordered, par-4 12th, shoving his drive dead right, along a cart path and into some bushes.

"Except for a case of brain lock, it wouldn't have been too bad," he said.

Irwin, who turned 45 yesterday and was an even greater long shot than Morgan, made an earnest and nearly successful run with his eagle-aided 69. He struck two irons directly at the flagsticks on the final two holes, for birdie chances of 10 and 15 feet that could have put him in a playoff. But the putts flirted with the cup.

"I had my chances," Irwin said. "I hit it where I wanted. All in all, I can't be upset."

Baker-Finch played six holes ahead of the final twosome and was hardly thought of until he vaulted onto the leader board with three straight birdies, at Nos. 6-8, to go eight under. He made up much of his ground on the three par-5s strewn around the course, birdieing each. The last came at the 13th, a downhill 524 yards, to move to 10 under.

But he could not find the green over his last three holes, plunging into bunkers on each. He scrambled for pars on Nos. 16 and 17. However, the cavern-like trap on 18 was another story, and he took bogey.

"It was impossible," he said. "Absolutely impossible."

That produced a two-stroke swing. Far away on the 13th hole, a rolling layout with split fairways, Irwin and Hoch each reached the green in two and barely missed eagle putts of about 20 feet. They walked away with birdies, pulling within a stroke of Baker-Finch. But neither could make a last putt fall, each finishing with five pars.

Moments later Morgan played the 13th. He bludgeoned a 3-iron that skidded to the back collar, then chipped to tap-in distance, a birdie that suddenly tied him for the lead. As he left the green he saw Baker-Finch's score go up on the board and knew another stroke would probably be good for a victory.

As Morgan stepped to the 15th tee, he told his caddie, "Well, this is where the golf course is going to begin today."

He stared over the rolling 467 yards, sloping downhill to a green lodged between two enormous trees. His 4-iron from the fairway bounced gently to 15 feet, and this time the putt slid in the hole.

That left only the bald, wind-whippped final holes. He flirted with danger at the 17th, playing safely to the front but leaving himself a 40-foot putt over two severe tiers. He cozied it to within inches.

At the 18th the bleak weather suddenly turned into a thunderstorm that he called "upsetting." He seized a 4-iron, intent on avoiding the left front bunker Baker-Finch had bogied from. He aimed 20 feet to the right of the hole, and cut it besides, so leery was he of the trap. The ball sailed through the green onto the back rough, leaving him 75 feet from the hole and buried in tufts of grass and clover.

But his sand wedge came out strongly and on line, curling past the lip. He considered the four-foot putt from every angle. It never quivered.

"I just wanted to give myself an opportunity to make the putt," he said. "It was a typical, easy putt to miss to keep from winning."

Instead, Morgan won a tournament that he has long been loyal to, playing in 10 of the 11 Kemper Opens held in the Washington area. He continually was among the leaders when the tournament was held at Congressional Country Club, and is among the few who have succesfully adapted to narrower, shorter Avenel. With yesterday's winnings he became the event's all-time leading money-winner with $322,925.

Morgan also is amid a personal record season with $498,682 in earnings. He is twice a runner-up, to Fred Couples in Los Angeles and to Tony Sills in a playoff in Houston. He has four top-10 finishes.

"I feel if I pace myself, I've got some years to play," he said.

..............1989......1990

Thursday....15,000....18,000

Friday......27,000....30,000

Saturday....40,000....40,000

Sunday......40,000....45,000

Total......122,000...133,000

Gil Morgan .........68.....67.....70.....69.....274

Ian Baker-Finch.....67.....72.....70.....66.....275

Scott Hoch..........68.....68.....69.....71.....276

Hale Irwin..........69.....73.....65.....69.....276

Denis Watson........67.....72.....70.....68.....277

Tom Kite............70.....70.....67.....70.....277

Complete results, Page C4