A LEAGUE OF HIS OWN; IRWIN JUST BEING IRWIN AS HE RALLIES TO WIN OPEN TITLE.

Byline: Eric Noland Daily News Staff Writer

Over the last two-plus years, no one has wielded more mastery of the Senior PGA Tour than Hale Irwin, and in the U.S. Senior Open, the tour's most important major tournament, he convened a clinic as to why.

Irwin mounted a relentless charge and delivered a spectacular finish Sunday at Riviera Country Club, obliterating the commanding lead of Raymond Floyd, holding off the surprising surge of Vicente Fernandez, and winning the championship the hard way - by rolling in a 12-foot, downhill birdie putt on the final hole, Riviera's dastardly 18th.

And then his celebration knew no bounds. Irwin pumped his right fist into the air. Then both fists. Once he got his hands on the great silver goblet that is this tournament's trophy, he wouldn't let go, even sitting with it wedged between his knees when he later met the press.

No wonder this guy has been so testy this entire weekend: Obviously, this championship meant much more to him than anyone realized.

It came on the strength of a 1-over-par total of 285, as he shot a 2-under round of 69 on the final day. That was one stroke better than Fernandez and two ahead of Floyd.

It also completed an impressive weekend rally. Irwin was well off the pace after opening with a 77 on Thursday. The previous worst score a U.S. Senior Open champion had to overcome in the first round was a 74.

The title is not an end-all for his career, Irwin said, ``but it kind of puts a stamp on where I've been trying to get to with at least those Open championships. . . . I guess it meant more to me because I wanted to be one of those few who won both.''

That would be Open titles on both sides of age 50. Irwin took the U.S. Open championship in 1974, '79 and '90, but the Senior Open had eluded him in 3-1/2 seasons on this tour, even though few other titles had.

Dominant? The adjective is almost inadequate to describe what he's accomplished. Since the start of '96, Irwin has played in 60 events, and this marked his 53rd top-10 finish and 16th victory. He's played 14 events this year and has finished in the top five in each and every one of them (this was his fifth win).

``I think it boils down to Hale's the best senior player out there. He showed it to the world today,'' said Floyd, Irwin's playing partner on the final day. ``He did what he needed to do. He played beautifully all day. . . .

``I've never seen a tour dominated the way he has done the last two years. It's incredible.''

That might sound like awe. More likely, it was shell shock.

Floyd began the day with a three-stroke lead, having put together two outstanding rounds of 70, followed by a respectable 73 on Saturday. But Floyd, whose approach irons landed well short of the green all day long, bogeyed two of the first five holes.

Irwin caught him within seven holes.

Sometime later came a surprise contender, Fernandez, an Argentine in his third year among the seniors (he played only on a short time on the PGA Tour). Fernandez, with a blistering final round of 3-under 68, created a three-way tie with a birdie on No. 16 and then took the lead when he sank a 15-foot par putt on No. 17 as both Floyd and Irwin were bogeying 13.

But Irwin didn't get all those victories in all those tournaments by being faint of heart. As he walked up the fairway at 15, he said, he told his caddie he would need a couple of birdies down the stretch.

Ordered, delivered. Irwin played left-right break to roll in a 25-foot birdie putt on 16, then averted what would have been an 18-hole playoff today by sinking that dead-straight 12-footer on 18.

Irwin nearly had three straight birdies to close out that charge. On a 25-foot attempt from the edge of the 17th green, the ball just caught the right lip, took a circle tour of the cup and kicked out. Irwin, in disbelief, flopped dramatically onto his back on the green.

``I always felt,'' he said of Open championships, ``that they test your management and patience - the mental part of your game.''

In that regard, he certainly recovered quickly to mount his assault on 18. It mirrored, in miniature, his recovery from that dreadful start on Thursday.

``There was no talking about it,'' Irwin, who ducked the press that day, said of his dismal first round, ``because I wanted it flushed from my mind. I wasn't that far out of it.''

The way he's been playing this tour, it was a cinch he was fully capable of playing his way back into the tournament. And winning it.

Irwin becomes the seventh player to couple a U.S. Open championship with a U.S. Senior Open title (the latter event began in '80). It's select company. The others: Arnold Palmer, Jack Nicklaus, Gary Player, Billy Casper, Lee Trevino, Orville Moody.

``My timing was not quite on this week,'' said Irwin. ``Coupled with my desire to win this event, that puts you on that edge of maybe you are trying too hard, maybe you are pushing it just a little bit. That's why I kept telling myself, `Back away from it. Back away from it.' ''

Once he had collected himself and locked his relentlessly precise game into place, the rest of the senior field probably had no chance.

As usual.

CAPTION(S):

4 Photos, Chart

PHOTO (1--Cover--Color) HALE OF A COMEBACK

Irwin's birdie on 18th gives him U.S. Senior Open title at Riviera.

(2) Hale Irwin rallied to win the U.S. Senior Open, his 16th title in 60 senior tournaments.

(3) Jack Nicklaus turns in best round of tournament.

(4) Raymond Floyd tosses his putter in disgust after missing a par putt on hole No. 5.

Myung J. Chun/Daily News

CHART: LEADERBOARD 

Phil J. Krugel/Daily News