NO ONE, but no one, will step on to the first tee at Royal Troon today with a greater spring in his step than Donald Barclay Howard, the man who is well into his second career as an amateur golfer. The self confessed former alcoholic who ruined his chances of major achievement by dint of his lifestyle first time around is making up for lost ground in admirable style.

Barclay is now a Walker Cup man, the holder of the Scottish Strokeplay Championship and will play in his first Open at the age of 44.

If he came off the eighteenth yesterday after his final practice round looking like a man with a couple of winning lottery numbers it was hardly a surprise.

He simply can't wait to get going. ''It has been great already, and that was only practise. The crowds are terrific and I started really well with four birdies in five holes.''

Howard partnered his pal, amateur champion Craig Watson, against two Scots professionals, Dean Robertson, who came off the final hole to discover he had been called in to the championship after hanging on in hope as first reserve, and Raymond Russell.

The amateurs won by two holes and picked up a tenner. ''It was great playing these guys,'' said Barclay, ''because you learn so much, even the way they block out the crowds.'' Howard loved the atmosphere. He got a kick out of the kids at every green waiting for his autograph, as well as the many people who wished him well.

''Even at the practice ground, you stand there and next to you is Fred Couples on one side and Gary Player on the other.''

Drawn with Peter O'Malley and Jim Payne, Barclay goes out at 2.45 in the afternoon. ''I'll be really nervous but I hope I put in a reasonable score.''

An hour and a half earlier, Dean Robertson will be off with fellow Scot Andrew Coltart and former winner of the championship, Mark Calcavecchia.

Robertson was told immediately after the practice round that he would be replacing Toshimitsu Izawa of Japan who had an injured finger.

''I am delighted,'' said the man from Paisley. ''I had been keeping my fingers crossed but it was a nightmare waiting to see if I would get in. I just tried to be as professional as I could.''

Robertson, who played all four rounds of the 1995 Open at St Andrews, one of the promising young Scots on the current scene, readily admits that he is ''not at the races'' when it comes to comparing players like Ernie Els and Tiger Woods but has enough self confidence to add: ''Yet.''

Craig Watson, who did not let the amateur side down at Loch Lomond last week, starts out at 8.05 with Australian Peter Lonard and American Jeff Maggert.

''I am really looking forward to it.'' He and Howard, who caddied for him in the final of the Amateur Championship, will have some tales to tell by the end of the week.

Another Scot, Stephen McAllister, has been told to be on stand-by as the new second reserve behind American Eric Rustand. Rumours about an injury which may force Spanish Angel Miguel Martin to withdraw were circulating last night, but Stephen would need two more to call off. It will be his turn to cross his fingers.

He's the tall guy in the baseball cap standing on the practice ground behind Nick Faldo or Ernie Els or Nick Price or Greg Norman, to name but four of his ''stable.''

He's the one peering through the video camera at slow-motion footage of those men and many others. Less famously, he's the man who is always late (friends say there are three time zones in America: east coast, central and ''David's''). He's the world's most famous golf teacher. And now, more than a decade after he transformed Faldo from pretty good to great, David Leadbetter is a walking conglomerate.

Books, videos, magazine articles, teaching aids of all shapes and sizes, instruction academies. You name it, his name is on it.

More to the point, he is also a man of strong opinions when it comes to the swinging of clubs and the ''playing'' of golf, two very distinct talents.

Leadbetter has an instinctive understanding of the former; a unique way of bringing out the best in his pupils when it comes to the latter. So no one is better qualified to pick the winner of this apparently wide-open 126th Open Championship.

''The champion this week will be a man capable of mixing his game up a little bit,'' he said yesterday while striding down the first fairway in Faldo's slipstream. ''By that I mean he will know which holes he can hit driver at and which he has to throttle back on - and he will stick to that plan no matter what. The tee shots are what set you up on this course. The rough is more threatening than it has been for a while at an Open venue.

''That brings the bunkers into play more. Balls tend to run into the sand from as much as 20 yards away, so the traps are much 'bigger' than their physical size.

Patience, according to Leadbetter, is another attribute this week's winner will have. ''Take the fifth hole,'' he said. ''If the wind is coming off the water from right-to-left and the pin is cut on the right side of that green, the players will have to accept that a 35-foot putt is pretty good. Aiming for the flag means the ball has to start out over the beach - and that is courting disaster.''

We've got game-plan and patience. It sounds like ''Lead'' is describing one Nick Faldo. But not necessarily. Surprisingly, Leadbetter feels there are as many as 20 potential winners this week. But they fall into different categories.

''Most probably the winner will come from what I call the 'magnificent seven,' he said. ''They are Tiger Woods, Ernie Els, Tom Lehman, Colin Montgomerie, Nick Price, Nick Faldo and Greg Norman. Below that there is another layer of players. Men like Davis Love, Justin Leonard and Phil Mickelson, Steve Elkington, Jose Maria Olazabal, Brad Faxon, Frank Nobilo, Ian Woosnam, Bernhard Langer and, maybe, youngsters like Thomas Bjorn and Lee Westwood. So you've got an upper and lower deck of potential winners.''

Lest it be thought he was getting into the realms of prevarication, Leadbetter was more than happy to name his top-five contenders and one dark horse. In order, they are:

1. ERNIE ELS: ''Ernie is obviously playing great right now. He won his last two events in the States and was second at Loch Lomond last week. More importantly, he isn't the sort of player who plays well one week then disappears for six months. During the PGA at Wentworth in May, he was just starting to get moving in the right direction. Ernie has great all-round ability. He's long; he's a great long-iron player and he has a deft touch for a big man. There are no gaps in his game. He has the temperament and the experience, too. He was second last year and I know that loss hurt. ''

2. TOM LEHMAN: ''Last year's win gave Tom a taste of what majors are all about. He was very close at the US Open this year and, although you can argue he hit a couple of loose shots towards the end, I would say that he didn't lose; Ernie beat him.

Tom is a class player, strong, too. He likes the different conditions over here which many of the Americans don't. His confidence after the win at Loch Lomond last week will be very high.''

3. COLIN MONTGOMERIE: ''Colin's coach, Denis Pugh, could be the difference for him. Denis is a very calm individual who will help Monty in that respect. They seem to be good together and Denis has been clever enough to get Colin focusing on the strong points of his game. Colin needs the people around him to tell him how good he is. If he can perform at his usual level, especially with the intimate knowledge he has of the course, he'll be right there.

''Playing at home has to help him. It's hard to imagine him having to spend too much time looking for the lines on the greens. In fact, he should be able to play here without a yardage book. That's a great advantage. But it's not the course or the other players Colin has to beat, it's the battle with the little beasties inside his head.

4. GREG NORMAN: ''Greg is playing really well right now, which will help him forget the two missed cuts he's had in the majors so far this year. He's always very relaxed here. The pressures on him aren't quite the same as in the States.

He feels at home in Britain. He really started his career over here and has done well in every European Tour event he has played in this year.

''As for his swing, Greg and I have worked to free up his action. Last year he was spending so long over the ball at address it was almost painful to watch. Now he's a lot quicker to pull the trigger. He doesn't have to think about his swing before he hits the ball.''

5. NICK FALDO: ''No one has a better record than Nick in this event. He's feeling good, too. He blew off a little bit of steam last week, just as he did before winning at Augusta last year.

''Still, it is true to say that he hasn't had quite the 100 percent focus that he once had. Little things have been annoying him, but he seems very geared up this week. He's hitting it well and made a lot of birdies in practice on Tuesday. We've been working hard on his putting, too. Nick is focusing on keeping the clubhead and his hands low during the stroke.

And a dark horse? ''Payne Stewart,'' said Leadbetter immediately. ''He's experienced. He played well last week. He likes links golf. He's got a lot of game and he's dying to get into the Ryder Cup team.''

Hang on, though, what have we forgotten? You know who, of course.

''Doing well in an Open is very often about experience rather than just pure talent,'' said Leadbetter. ''And this course is not just about ball-striking. For those reasons I think Tiger will have to wait at least one more year.''

I told you he had strong opinions.