PHOTOPhotograph by Bob Martin for Sports IllustratedThree Down ... After tailoring his game to the links at Muirfield, Phil Mickelson shot a dazzling 66 on Sunday to move within one major of a career Grand Slam By Alan Shipnuck Phil Mickelson conducted himself with his usual dignity in the immediate aftermath of his heartbreaking near miss at last month's U.S. Open. But in the privacy of his home he felt the full weight of defeat. "He stayed in bed for two days with this blank look on his face," says his wife, Amy. "He was a shell of himself." On the third day Mickelson finally rose, to leave for a long-scheduled family vacation to Montana. Part of Mickelson's charm is that, despite all the trappings of approaching middle age, he has never really grown up. Alongside his three kids he lost himself in whitewater rafting, rock climbing, archery, skeet shooting and various other kinds of fun. When a refreshed Mickelson, 43, returned home to Rancho Santa Fe, Calif., he was ready to go to work, which is a very short commute: In his backyard he recently built a practice facility that stretches for 200 yards, with numerous bunkers and five greens. "Each has a different grass and a different design style," says Mickelson's manager, Steve Loy. A full-time greenkeeper tweaks the putting surfaces to Mickelson's every whim. Before this year's Masters one green was Stimping at 14.5 to replicate Augusta National's speed. Since turning 40 Mickelson has been beset with putting problems, leading to dalliances with a belly putter (2011) and an unorthodox claw grip ('12). But this season Mickelson has been saying he's putting better than at any point in his career, and a lot of that is due to old-fashioned hard work, with a dash of Cali swag. "He loves to go out there in shorts and flip-flops," says Amy. "He just loves to practice." How does he continue to soldier on? "Because he's Phil," says his careerlong caddie, Jim Mackay. "He's resilient. And there are birdies to be made." Indeed, two weeks ago Mickelson turned up for the Scottish Open—at a firm, fast, rollicking course in the Highlands—and played a dizzying variety of shots en route to his first victory on European soil since a B-list event in France in 1993. That British Open tuneup was part of Mickelson's ongoing education in links golf. For most of his career he had tried to impose his game on the course, pounding towering drives and high, spinning iron shots, wind be damned. Only in recent years has he learned to embrace the ground game and strategic play necessary on these ancient courses where land meets the sea. "He's the most creative player in the game," says swing coach Butch Harmon. "He just needed to change his thinking." Muirfield, the site of the 142nd Open, presented the ultimate test. Most Open venues are blondes, with long fescue waving in the breeze, but Muirfield was a brunette, the dying greens and fairways turning browner by the day thanks to an ongoing heat wave. Mickelson played well but not quite well enough over the first three rounds; at two over par he was tied for ninth, five off Lee Westwood's lead, and staring up at Tiger Woods (one under) and Adam Scott (even), among others. But Sunday, Mickelson was typically jaunty. On his way out the door he told Amy, "I'm gonna go get me a claret jug." A mistake-free front nine put him in position, and then he simply blew everyone else off the course with a back-nine 32 that was every bit as thrilling as his closing 31 at the 2004 Masters. Mackay, fighting back tears afterward, called the 66 the best round his boss has ever played, and Zach Johnson added, "That will go down as one of the greatest rounds ever at a major championship." Mickelson's five career majors tie him with two players he has patterned himself after, swashbuckling escape artist Seve Ballesteros and Byron Nelson, the ultimate golfing gentleman. Mickelson is now three quarters of the way toward becoming the sixth player to win the career Grand Slam—only the U.S. Open is missing from his trophy case. But for all the historical import, this victory was deeply personal for Mickelson. "I'm so proud to be your champion," he said at the trophy ceremony. "I never knew if I'd be equipped, if I'd have the shots, if I'd have the opportunity to win this tournament. To play some of the best golf of my career, and break through and capture this claret jug is probably the most fulfilling moment of my career." Two hours later, having cured his U.S. Open hangover in the most audacious way imaginable, Mickelson found himself at a party holding a flute of champagne. Amy motioned toward the trophy her hubby was lugging around. "Why don't you drink it out of that?" she said. Phil looked around the room at the assembled tweedy gents from the R&A. With a little smile, he said, "Not here." But definitely somewhere else. And soon.PHOTOPhotograph by Paul Childs/Action Images/ZUMAPRESS.comA determined Ian Poulter made a late charge, shooting 67 on Sunday to finish four strokes back.PHOTOPhotograph by Thomas Lovelock for Sports IllustratedAdam Scott fell out of contention with four straight bogeys on the back nine on Sunday.PHOTOPhotograph by Mike Egerton/PA Photos/LandovDeep trouble was easy to find in Muirfield's bunkers, as Miguel Angel Jiménez discovered on Saturday.PHOTOPhotograph by Thomas Lovelock for Sports IllustratedAngel Cabrera's Friday bogey at the treacherous 18th wasn't all that bad: The hole generated a tournament-high 33 scores of double bogey or worse.PHOTOPhotograph by Bob Martin for Sports IllustratedTiger Woods looked poised to pounce after Saturday's strong finish, but a final-round 74 meant his streak of majors without a win would run to 17.PHOTOPhotograph by Thomas Lovelock for Sports IllustratedA strong third round—which at times Woods couldn't bear to watch—gave Lee Westwood the lead heading into Sunday, but a 75 dashed the Brits' hopes of a homegrown winner.PHOTOPhotograph by Thomas Lovelock for Sports IllustratedMackay, who has been on Mickelson's bag for more than 20 years, said Sunday's round was the best he's seen his boss play.PHOTOPhotograph by Thomas Lovelock for Sports IllustratedMickelson made good on his Sunday-morning promise to his wife to bring home another piece of hardware.