Larry Nelson shot a course-record, 9-under-par 63 today and took a four-stroke lead in the first round of the $1.35 million Canadian Senior Open.

Nelson's round included holding out for eagle on the par-5 12th hole as he broke Hale Irwin's record of 65, set during the 1973 Canadian Open on the Rouville Course of the Richelieu Valley Golf Club.

Irwin shot a 67 Thursday for a share of second place with Kermit Zarley and Jim Ahern. Irwin's round was his 12th straight under 70, surpassing Lee Trevino's Senior PGA Tour record set in 1992.

"I hit two good shots and made birdie right off on the first hole and that seemed to set the tone for the whole day," said Nelson, who won a U.S. Open and two PGA Championships among his 10 career victories on the PGA Tour.

In two years on the over-50 circuit, Nelson has five victories, including earlier this year in the GTE Classic and Bruno's Memorial. He is fourth on the money list with $1,132,908.

Nelson insisted he hasn't played well, and only fixed his swing this week when he reverted to the swing he had early in his PGA career.

"I started swinging down and across and let gravity take over and I started hitting the ball solidly," he said. "I feel comfortable with that because that's the way I used to play."

The top seniors were predicting low scores on the 6,705-yard layout, and they were right. Eight players were at 68 and 14 shot 69s.

Forty-two in the 78-man field broke par.

"The story is the greens," Irwin said. "They're slow and that's why you're seeing a lot of red numbers.

"There's no fear on the greens of putting it past the hole. And the weather (muggy, with no wind) is ripe for low scores. All the conditions are there."

Ahern, who played on the PGA Tour in the early 1970s, used six birdies and a bogey to place among the leaders.

"I probably missed three or four birdie putts under 10 feet, but then I made some longer ones," said Ahern, who lives in Phoenix. "A 67 is as bad as I could have scored today with how well I hit the ball and putted."

Nelson dismissed the notion that the course was too easy.

"You're seeing a lot of low scores because the course is in perfect condition," Nelson said. "The greens are slower than we normally play, but for me, it's set up perfectly.

"The scores are low because the greens are soft and the course is playing short, but you still have to make good shots, hit the fairways and take advantage of the opportunities you get."

AP