ARDMORE, Pa. — The U.S. Open is known as the toughest test in golf, and it's even more difficult when more than 72 holes are required.

Willie Anderson won the first of 33 playoffs in U.S. Open history with an 85 to win by one shot over Alex Smith in 1901 at Myopia Hunt north of Boston. Tiger Woods won the most recent playoff, a 19-hole thriller over Rocco Mediate on a badly injured left leg.

Arnold Palmer was in three U.S. Open playoffs — and lost them all. The great Bobby Jones twice lost U.S. Open playoffs by a single shot.

There have been a few dull playoffs along the way, such as Jones winning by 23 shots in a 36-hole playoff over Al Espinosa, and Retief Goosen beating Mark Brooks in 2001 at Southern Hills. Both wore khaki pants and a white shirt.

Here are five of the most memorable playoffs in U.S. Open history:

5. BILLY BURKE AND THE LONGEST OPEN

Here's one U.S. Open record that will never be broken — in what amounts to golf's version of a doubleheader, Billy Burke had to play the equivalent of two 72-hole tournaments to win the 1931 U.S. Open at Inverness.

Burke closed with a 73 to make up a two-shot deficit against George Von Elm, setting up a 36-hole playoff the next day. This was one year after Von Elm lost in a 28-hole match in the U.S. Amateur at Merion. He was no stranger to overtime.

In a see-saw battle, Burke finally emerged with a one-shot lead with a birdie on the 15th hole of the second round, only for Von Elm to birdie the 18th hole to match him at 7-over 149. That led to another 36-hole playoff the next day, and Burke started poorly with a bogey and double bogey. He finally caught up to Von Elm on the front nine of the afternoon round, and pulled ahead for good when Von Elm bogeyed the 14th hole. This time, Von Elm was out of heroics. Burke shot 148 to win by one shot.

They had to play 144 holes over five days. The next year, the USGA voted to return playoffs to 18 holes.

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4. ALL HALE THE THREE-TIME CHAMPION

Hale Irwin was 45 and considered a part-time player on the PGA Tour, winless in more than five years. A two-time U.S. Open champion, his exemption had run out the previous year, so the USGA awarded him a special invitation to the 1990 U.S. Open at Medinah.

Four shots behind going into the final round, Irwin ran off four straight birdies on the back nine and looked like he would come up short when his 7-iron to the 18th was some 50 feet away. He made the putt for a 67, and ran toward the fans and gave them high-fives. It got him into a playoff with Mike Donald at 280.

Irwin again was on the ropes, two shots behind with three holes to play. Irwin hit 2-iron from 210 yards to 6 feet for birdie on the 16th hole. Donald went from the rough to a bunker and blasted out to 15 feet on the 18th hole, giving him a par putt to win the U.S. Open. He missed, leading to the first sudden-death playoff in championship history. Donald missed his 20-foot birdie putt, and Irwin made his 10-footer for birdie.

He remains the oldest U.S. Open champion, and the last player to win after getting a special exemption.

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3. THE PLAYOFF THAT PUT AMERICAN GOLF ON THE MAP

The 1913 U.S. Open at The Country Club remains the most significant major championship in history. Francis Ouimet, the first amateur to win the U.S. Open, took down British heavyweights Harry Vardon and Ted Ray, a win that put golf on newspaper front pages.

The three-man playoff was set up by Ouimet's 74 in the third round to make up a five-shot deficit, and a 79 in the final round to match Vardon and Ray at 304.

They all went out in 38, and Ouimet took the lead for good on the 10th hole when the British stars both three-putted for bogey. Ouimet gained another stroke on them with a par on the 12th hole, and Vardon birdied the next hole to trail by one.

It came down to Ouimet and Vardon with two holes to play, and the 17th hole proved pivotal. Vardon tried to cut the corner of the dogleg, found a bunker and had to pitch out sideways on his way to a bogey. Ouimet made a birdie putt, and suddenly the lead was three shots going to the final hole.

Ouimet closed with a par for a 72, while Vardon made double bogey for a 77, making the margin look more than it really was. Ray shot 78.

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2. HOGAN COMPLETES COMEBACK AT MERION

There is a famous photo of Ben Hogan hitting 1-iron into the 18th green at Merion in the 1950 U.S. Open for a par. But his comeback didn't end there. All that did was get Hogan into a three-way playoff with Lloyd Mangrum and Tom Fazio.

Hogan putted so poorly in the final round that he had his brother, Royal, ship a brass putter to Merion. The club arrived before the playoff, but not in time for Hogan to practice with it, so he stuck with his old putter.

Hogan had a one-shot lead through 13 holes of the playoff. Fazio made four bogeys down the stretch and was out of the picture, though Mangrum hung tough. He responded to a bogey on the 14th with a birdie on the next hole to stay one shot behind. On the next hole, everything changed. Mangrum marked his ball so Fazio could finish, and then marked it again to blow a bug off his ball. That was against the rules at the time — for the U.S. Open, players only were allowed to mark the ball if it were in a competitor's line — and Fazio was assessed a two-shot penalty. Hogan closed with a 69 and won by four shots over Mangrum, while Fazio shot 75.

Hogan, in a near-fatal car accident just 16 months earlier, said this U.S. Open meant the most to him because it proved he could still win.

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1. ON WOUNDED KNEE AT TORREY PINES

Only after Tiger Woods captured the 2008 U.S. Open at Torrey Pines did anyone realized how unlikely it was that he even played.

He had arthroscopic surgery on his left knee two days after the Masters to clean out cartilage damage, but did not want to repair ligaments so he could finish out the majors. Two weeks before the U.S. Open, he suffered a double stress fracture in his left leg.

Woods defiantly ignored doctors' advice to rest for six weeks, telling them he was going to play the U.S. Open and "I'm going to win."

It wasn't easy. His knee began to buckle without warning, but Woods played on. He turned a five-shot deficit into a one-shot lead over the last six holes of the third round, including a 70-foot eagle putt on the 13th and a 30-foot eagle putt on the 18th. But he struggled in the final round, and came to the par-5 18th one shot behind Rocco Mediate. Woods missed the fairway, laid up in the rough, and then hit a sand wedge to 12 feet. He made it to force a playoff, one more round on tender legs.

Woods built an early lead on Monday, only for Mediate to rally and take a one-shot lead into the final hole. Woods needed another birdie, and this time reached the green in two for a two-putt birdie to force extra holes. They went to the par-4 seventh, where Mediate found trouble off the tee and on his second shot.

Woods made par to win the U.S. Open. One week later, he had surgery that ended his season. He has not won another major since.