BEIJING • Michael Phelps ended his swim into history – and into the hearts of millions of Americans – by winning his eighth gold medal.

“It’s been nothing but an upwards roller coaster,” Phelps said Saturday night a few minutes after winning his final gold in the 400-meter medley relay. “It’s been nothing but fun.”

The eight medals rank as a record for a single Olympics, breaking the mark Phelps had shared with American swimmer Mark Spitz, who won seven golds in 1972.

Phelps’ last gold had a touch of drama. The Americans have won every Olympic gold in the 400 medley relay, but they trailed when Phelps began the third leg, the butterfly.

He has delivered over and over during this stupendous swimming week. This performance was no different.

At the wall, Phelps was third, but gaining. By the time he finished his leg, Phelps had made up seven-tenths of a second, and the United States was on its way to victory.

Phelps gave credit to his teammates for his record.

“These guys were amazing,” he said. “These guys made it possible. The relay really made it possible. It shows how much teamwork and togetherness we have. It’s amazing to be part of it.”

The relay team – Aaron Peirsol, Brendan Hansen, Phelps and Jason Lezak – swam to a world-record time of 3 minutes, 29.34 seconds, easily beating Australia (3:30.04).

A few minutes after his victory, Phelps went through a familiar routine. He stood smiling on the medal stand before marching through a long line of photographers to embrace his mother.

Spectators at the Water Cube – a wild, futuristic structure – rose to cheer America’s Swim King. He held his arms high.

It had been a wild week of triumph. He came within a few atoms of ending his quest for eight golds in the 100-meter butterfly Friday, when he defeated Milorad Cavic by the barest of margins.

Now, his quest was over.

“The whole thing, every race, one after the other from winning by one-hundredth of a second yesterday to finishing it off with a world record – it’s an amazing experience and something I’ll have forever.”

Michael Phelps celebrated the U.S. team’s gold-medal finish in the 400-meter medley relay on Saturday. It was Phelps’ record-breaking eighth gold medal of the Beijing Games. Photo by MARK REIS, THE GAZETTE