One last lurch. One desperate dive at the wall. Caught between a Serb and a second place, Michael Phelps gathered up one final stroke for the ages, one last swoosh toward immortality.

It looked like he was done.

Milorad Cavic, a relatively unknown Serb swimmer liviing in California, was about to put an end to this unprecedented and seemingly inevitable gold medal quest of Michael Phelps. The 100 butterfly was going to be Phelps' Waterloo.

Cavic led by .07 over Phelps as they made the turn. Phelps was in seventh place and inside the Water Cube, American fans were in a panic. The picture in front of them was all wrong.

It takes a moment like this to truly measure the greatness of an athlete. Greatness needs to be tested. It needs a Cavic, someone who isn't afraid of the legend swimming next to him. Greatness needs a gut check. Life is easy when every win is a rout. But how does Greatness act under pressure? How does Greatness react to adversity.

Here was Cavic swimming unafraid. Leaping ahead of Phelps. Cavic, the perfect foil, heartlessly playing the spoiler. It was a truly spectacular, Olympic moment.

But Greatness understands the circumstances. Greatness adjusts. Greatness has deep, deep reserves of willpower. Greatness finds a way past all of the adversity. It overcomes..

In the final 10 meters, Phelps was a mess. He looked done. The timing of his strokes was off. In a race that was going to be decided by a hundredth of a second, it didn't look like he had the time or the distance to get to the wall first.

But this is where Greatness happened.

Phelps knew how to win this race. Cavic didn't. Timing be damned, Phelps practically threw himself at the wall and touched just below the surface of the water. Cavic glided in, probably secure in the knowledge he had won. He rode his last stroke like a wave.

For a moment, it looked as if Cavic had won.

Phelps hit the wall, tore off his goggles, spun toward the scoreboad and saw the result. The crowd, certain he had lost, gasped. Then it gasped again when the results appeared.

Phelps was first in 50.58. Cavic finished in 50.59.

Some immediately thought the fix was in. Serbian officials filed a protest, but referee Ben Ekumbo said the Omega timing system had worked.

Indeed, Phelps won. NBC's super slow-motion proved as much.

Even the good-natured Cavic said of the Serbian protest, "I would drop the protest. I'm stoked with what happened. I'm very, very happy."

Continuing the protest would have been sour grapes. And this moment was too sweet for sour.

This is what we hadn't seen from Phelps. We had seen his remarkable natural ability. We had seen the fruits of his long, painful hours of training. We knew he was among the greatest Olympic athletes of all time and knew he had won more gold medals than anyone ever.

But in his quest for eight in Beijing 2008, we hadn't seen THIS. We hadn't gotten a good look at his heart. We didn't know if, even he could react to athletic adversity this drastic.

All of us were pretty sure we would see the most remarkable 100 of all time on Saturday, but we thought it would be on land, at night, in the 100-meter final featuring the fleetest triumverate ever -- Usain Bolt, Asafa Powell, Tyson Gay.

Turns out the most remarkable 100 was in the pool..

Phelps tied Mark Spitz' 36-year-old record, winning his seventh gold medal by this .01 second. He will go for his eighth-and-final gold on Sunday morning, swimming a leg of the 400 medley relay.

But ridiculous as it is to say, I believe, Phelps' Beijing Olympics won't be defined by the unprecedented eight golds, but by one last-ditch lurch that got him to the wall ahead of Cavic..

"I think the biggest thing is that when someone says you can't do something, they don't know," Phelps said in a brief appearance in the mixed zone after the race. "But this just shows you that anything is possible. When you put your mind to something you can do anything."

In this race we learned even more about Michael Phelps. Under the most difficult circumstances, he found something else inside of him. He found a desperation that even he couldn't describe.

"It seems like every day I'm in some sort of dream world," he said. "I have to pinch myself to make sure it's real. I'm just happy to be in the real world. When I did chop that last stroke I thought it cost me the race. But it turned out to be exactly the opposite. If I would have glided in, it would have been way too long."

Greatness was pushed inside the Water Cube. Michael Phelps discovered a show-me swimmer from Serbia, who thought he just might be able to beat the best man ever on water.

For 99 meters, Milorad Cavic was right.

But Greatness finds ways to the wall. Greatness finds ways to win.