WILL IT BE TWO-MAN RACE?; IRWIN, MORGAN STRONGLY FAVORED.

Byline: Dave Shelburne Daily News Staff Writer

A generation ago, it was Jack Nicklaus and Arnold Palmer - shooting it out for nearly every major championship on the PGA Tour.

They're in the field again this week for the 19th U.S. Senior Open at Riviera Country Club. But this time, the big guns are Hale Irwin and Gil Morgan - the Jack and Arnie of their second-chance era.

``If I had to pick a man right now, Gil's been in form,'' said defending champion Graham Marsh. ``And I'm not saying that Hale can't win the championship.''

Between them, Irwin and Morgan have won eight of the 22 events on the 1998 PGA Senior Tour (four apiece) and combined for more than $3 million in official earnings in this year's age 50-and-over competition.

Marsh, hometown hero/putting wizard Dave Stockton, longtime amateur star Jay Sigel and rookie phenom Larry Nelson could be factors to the finish. So, too, might big-match player Raymond Floyd or even the 58-year-old Nicklaus, who has won a combined 28 majors in the amateur, PGA Tour and PGA Senior Tour ranks.

And don't rule out a long-shot champion in an event that has produced upset Senior Open winners Larry Laoretti and Simon Hobday in this decade. Marsh likes the chances of Australian David Graham. Long-hitting John Jacobs, England's Brian Barnes and South Africa's Hugh Baiocchi all have posted their initial senior tour wins within the last year.

But look for Morgan and Irwin to command at least as much attention as Riviera's refurbished greens, its ball-eating kikuyu rough and the capricious winds that can howl through the towering eucalyptus on this storied Pacific Palisades course.

Will this be a two-man race?

Marsh thinks it might be, considering how Riviera is set up this week - 6,907 yards in length with fairways barely 40 yards wide, 3-1/2-inch rough and greens nearing 11 on the stimpmeter.

``Morgan has the advantage here because of his length,'' said the defending champion. ``Irwin has an advantage here because of his great iron play.''

Marsh thinks Riviera's greens, which have improved considerably with the attention of new superintendent Paul Latshaw, could play a large role.

``It becomes a little bit of a cliche to say it comes down to putting,'' he said. ``If you don't bring your putting game with you on a particular week, you can finish well. But on a golf course like this, it's probably unlikely that you're going to win.''

The way Marsh sees it, even a premier putter like tour leader Irwin had best be at his best.

``Hale is a great putter, but even for Hale to win he has to make clutch putts,'' Marsh said.

Irwin likes to put first things first and worry about those putts in their time.

``You have to get there,'' said the man who leads the senior tour in hitting greens in regulation. ``You have to hit the ball in the fairway, and you have to hit the greens.''

``It is going to require keeping the ball in play,'' said Morgan, who agrees with Irwin on the importance of hitting fairways and greens.

But Morgan disagrees with the notion this will be a two-man race, even though he and Irwin rank among the top five in six of the tour's 10 statistical categories.

``I don't know about that,'' he said of the two-man theory.

``We have got quite a few players that have played well here in the past.''

Former Riviera head pro Peter Oosterhuis suggests a third member to the big two of Irwin and Morgan. He thinks Riviera might prove the toughest competitor of all this week.

``The kikuyu grass can thrive in the summer,'' said Oosterhuis, the former European Tour star who worked at Riviera from 1991-93.

``I can certainly remember having some impossible shots around the greens, where it was a full swing to hit the ball 10 yards.''

If not the kikuyu, it's the length.

``It's pretty long on the card, and it is playing long,'' said Oosterhuis, who thought a final score over par was not an unreasonable expectation.

``I think it is possible,'' he said. ``It does depend a little on the speed of the greens. If they get fractionally faster than they are, that will affect the scoring immediately.''

CAPTION(S):

2 Photos, Box

PHOTO (1--Color) Arnold Palmer putts on the 10th hole below the clubhouse during practice play Wednesday at Riviera.

Mark J. Terrill/Associated Press

(2) Gil Morgan, one of the favorites to win the U.S. Senior Open at Riviera, eyes a shot during practice Wednesday at the club.

Tom Mendoza/Daily News

BOX: TEE TIMES