By Mark Garrod, PA Sport Golf Correspondent, Chicago

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Tom Watson, aged 53 and 21 years on from winning the United States Open, unbelievably equalled his lowest-ever round in the championship on Thursday.

In a round full of drama - nothing like the boring golf Padraig Harrington said would win - Watson returned a five-under-par 65 at Olympia Fields near Chicago to share the lead with fellow American Brett Quigley.

Playing in the event for the 30th time and without a round in the sixties since 1994, Watson holed his approach to the 458-yard 12th for an eagle two and then had two birdies in the last three holes to complete a dream day for himself and caddie Bruce Edwards.

The first of those was an amazing 35-foot putt that looked to have stopped on the edge. But as Watson walked forward the ball toppled in.

Edwards was a story in himself. Last autumn he had amyotrophic lateral sclerosis diagnosed and he was given permission by the United States Golf Association to use a cart - as he did in last week's Senior PGA championship - but declined.

Watson and Quigley, who has yet to win on the US Tour, finished the opening round one ahead of fellow Americans Justin Leonard and Jay Don Blake.

Colin Montgomerie had a chance to be right in the thick of things as well when he stood three under with four to play earlier in the day, but he bogeyed two of them for a 69.

Nevertheless, it was Montgomerie's first sub-70 round in America this year and it shook off the misery of recent weeks - of virtually the whole season, in fact - on his return to his favourite event.

His 69, matched by Padraig Harrington and later Sergio Garica, put them one ahead of defending champion Tiger Woods.

The story of the day threatened to be Quigley's playing partner Londoner Brian Davis on his first appearance in a major in the United States. Having qualified last week and then having flown home to play in the British Masters, Davis pitched in for an eagle on the first and birdied the next three.

But the magic disappeared with a double bogey five on the fifth and he finished with a one-over 71.

Montgomerie has missed his last two halfway cuts in Europe, something that had not happened for five years, and was back in the land where he played seven tournaments at the start of the year and made it to the weekend only once.

But birdies at the 12th and 13th - like Woods he opened on the back nine - had those watching thinking not so much of troubled times as his record in the event and his form at last September's Ryder Cup.

Montgomerie, top-scorer for Europe in the victory at The Belfry, was third on his US Open debut in 1992, lost a play-off to Ernie Els in 1994 and was then runner-up to the South African again in 1997.

After turning in a two-under 32 he picked up his next stroke on the 576-yard first with a five-foot putt.

It was to prove his last birdie, however, and after taking six on the long sixth - he said afterwards he should have hit three-wood off the tee rather than driver - he missed the fairway at the ninth and bogeyed that as well.

"Disappointing, but I would have taken 69 before the start and that's the important thing," he commented in the locker room, having decided not to give a more formal media interview.

"The crowd were great (he has not always said that on this side of the Atlantic) and I like the course."

He also attributed part of his return to form to the presence not only of coach Dennis Pugh, but also psychologist Hugh Mantle.

"Hugh and I have worked together for eight years and he knows me very much - we work as a team. However you want to disguise it, the last two weeks were not good and I am one of those people not ashamed to ask for help.

"It's a matter of finding the positives, although it was very difficult to find them out of the Forest of Arden last week."

Harrington birdied two of his first five holes, three-putted the difficult ninth and then, after grabbing another birdie straightaway with a curling 10-footer, finished with another three putts.

"It's never nice to bogey the last - it leaves a sour taste," said the Dubliner. "It was all going nicely, but I seemed to get tired and struggled for focus."

Biggest gallery of the day, naturally, went with Woods and world number two Ernie Els, both double winners of the title.

The South African shaded it by one with his 69, having 17 pars and a lone birdie at the short 15th (his sixth), while Woods matched Harrington by bogeying the ninth and 18th, but produced a spectacular eagle three on the 555-yard sixth.

He left himself 250 yards to the flag there and struck a three-iron to 20 feet - although he admitted afterwards he came off the shot a tad!

Justin Rose began his debut by going to the turn in a three-over 39, but then came home in a superb three-under 31.

"I am delighted with that because I am not playing well," said the 22-year-old. "I don't really know where the ball is going. I am proud of myself - I stayed patient and I have not been able to do that of late."

Darren Clarke also mounted a recovery act to level par after bogeying two of his first three holes, but it was a bad day for Paul Lawrie, Nick Faldo and Paul Casey.

Lawrie and Faldo had 75 and Casey struggled to a six-over 76.

Collated first-round scores (USA unless stated, par 70):

(x) denotes amateurs

65 Brett Quigley, Tom Watson

66 Justin Leonard, Jay Don Blake

67 Stephen Leaney (Aus), Jim Furyk

68 Tom Gillis, Ian Leggatt (Can), Mark Calcavecchia

69 Hidemichi Tanaka (Jpn), Cliff Kresge, Tom Byrum, Ernie Els (Rsa), Loren Roberts, Billy Mayfair, Jonathan Byrd, Padraig Harrington (Ire), Colin Montgomerie (Gbr), Tim Clark (Rsa), Robert Damron, Len Mattiace, Sergio Garcia (Spa), Tim Petrovic, Fredrik Jacobson (Swe)

70 Chad Campbell, Tiger Woods, Vijay Singh (Fij), Bernhard Langer (Ger), Bob Estes, Craig Parry (Aus), Charles Howell, Justin Rose (Gbr), Fred Couples, JP Hayes, Jonathan Kaye, Joe Ogilvie, Darren Clarke (Gbr), Phil Mickelson, Scott Hoch, Stewart Cink, Eduardo Romero (Arg), Steve Lowery, Fred Funk, Brandt Jobe

71 (x) Ricky Barnes, Kevin Sutherland, Dan Forsman, Retief Goosen (Rsa), Spike McRoy, Darron Stiles, Dicky Pride, Brian Davis (Gbr), Richard Johnson (Swe), Thomas Bjorn (Den), Nick Price (Zim), Kirk Triplett

72 Trevor Immelman (Rsa), (x) Chris Baryla, Adam Scott (Aus), Olin Browne, Rod Pampling (Aus), Chris DiMarco, Marco Dawson, Doug LaBelle, Neal Lancaster, Chris Anderson, Mark O'Meara, David Toms, Kenny Perry, Lee Janzen, Corey Pavin, Dudley Hart, Angel Cabrera (Arg), Tom Kite, Joe Durant, John Maginnes, Jay Williamson, Ryan Dillon, Hiroshi Matsuo (Jpn)

73 (x) Bill Haas, Roland Thatcher, Steve Flesch, Rocco Mediate, Rory Sabbatini (Rsa), Brad Faxon, Doug Dunakey, Rob Bradley, Mike Weir (Can), John Rollins, Alex Cejka (Ger)

74 Bob Tway, David Smail (Nzl), Jeff Maggert, Bryce Molder, Scott McCarron, Grant Waite (Nzl), Jesper Parnevik (Swe), Bill Lunde, Geoff Ogilvy (Aus), (x) Trip Kuehne, (x) Hunter Mahan, Rich Beem, Michael Campbell (Nzl), Jose Maria Olazabal (Spa), Jeff Sluman, Woody Austin

75 Brad Elder, Roy Biancalana, Robert Allenby (Aus), Jerry Kelly, (x) Luke List, Maarten Lafeber (Ned), Bret Guetz, Jason Knutzon, Cortney Brisson, (x) Chez Reavie, Paul Lawrie (Gbr), Nick Faldo (Gbr), Jay Haas, Shigeki Maruyama (Jpn), Stuart Appleby (Aus), Niclas Fasth (Swe), Anthony Arvidson

76 (x) John Holmes, Joey Sindelar, Dean Wilson, Larry Mize, Kent Jones, Tommy Armour, (x) Rick Reinsburg, Craig Bowden, Steve Gotsche, Mark Wurtz, Paul Casey (Gbr), Chris Riley, Davis Love, Scott Verplank, Brian Henninger, Geoffrey Sisk, Matt Seppanen

77 Brian Gay, Warren Schutte (Rsa), Chris Smith

78 Greg Hiller, Sean McCarty, Sean Murphy, David Duval, Billy Andrade, Bob Burns

79 KJ Choi (Kor), Toru Taniguchi (Jpn), Alan Morin

80 (x) Tom Glissmeyer

81 Don Pooley

Retired: Hale Irwin