SAN DIEGO -- In a week of epic moments at the U.S. Open, Tiger Woods delivered the biggest one yet.

It didn't bring him another major, just another chance.

Down to his last stroke Sunday afternoon at Torrey Pines, Woods rapped a 12-foot birdie putt that bumped along toward the hole and swirled into the back corner of the cup without an inch to spare.

In a career filled with clutch putts, this one put Woods into an 18-hole playoff Monday against Rocco Mediate, who was in the scoring room watching the 18th hole theatrics unfold on TV.

"Unbelievable," Mediate said. "I knew he'd make it."

They finished at 1-under 283, the first time since 2004 that someone broke par in a U.S. Open.

Mediate closed with an even-par 71, missing a chance to eliminate Woods when his wedge to the 18th stayed atop the ridge and left him a 30-footer that he two-putted for par.

It looked like it might be good enough when Woods and Lee Westwood of England, both one shot behind, hit into the bunker on each side of the fairway on the 527-yard closing hole and had to lay up.

Westwood went first from 15 feet above the hole, but his putt lost speed and turned away. He shot 73.

Woods had such a clean lie in the bunker that he might have gone for the green in two if the U.S. Open wasn't on the line. Instead, he hit a terrible shot to the right and into the rough, and had to hope that his 60-degree wedge was the right choice. It settled 12 feet away, giving him yet another putt that he couldn't afford to miss.

"A little wobbly down there," he said of the poa greens, a grass that gets bumpier in the afternoon sun. "I played probably 2½ holes outside right. Just take it back and make a pure stroke, because once it starts slowing down there ... you don't know what's going to happen. All I could control is my stroke."

He started to backpedal as the putt neared the hole, paused to make sure it was in, then clenched and pumped both fists toward him in rapid-fire succession, screaming with joy with his face to the sky.

Woods wasn't sure he could make it 72 holes on a left knee that has progressively gotten worse since the opening round, his first since surgery to clean out cartilage on April 15. He was never more thrilled to get a chance for 18 more.

He shot 73 and will be in a playoff for the third time in a major, this one 18 holes of stroke play on Monday.

Can his knee take one more round of golf?

"It's going to have to," Woods replied.

The 50,000 fans at Torrey Pines, who thought they had seen it all during a most remarkable week, now get a little bit more.