BEIJING - Michael Phelps hit the wall and turned for home, once again under world-record pace and looking ever more like nobody is going to stop him at the Beijing Olympics.

With the crowd at the glistening Water Cube rising to its feet and roaring louder with every stroke, the superstar swimmer powered through the final leg of the 200-meter individual medley Friday to win his sixth gold medal in six races and pull within one of the record seven that fellow American Mark Spitz won at the 1972 Munich Games.

"If it were all over today, he'd be the greatest Olympian who ever lived," his coach, Bob Bowman, said.

Phelps will swim for immortality in the 100 butterfly Saturday, followed by the 400 medley relay Sunday - an event the Americans have never lost in the Olympics.

He already owns a dozen Olympic gold medals, three more than any other athlete in history.

"I'm down to the last two races and I'm just going to try to rest and recover the best that I can and prepare myself for those two races," he said.

Fellow American Ryan Lochte was expected to perhaps challenge Phelps in the 200 individual medley, having clocked a faster time by 0.01 seconds in qualifying. But Lochte won a gold medal and set a world record in the 200 backstroke barely 20 minutes before his race against Phelps, and his challenge never materialized.

"I wasn't planning on the back hurting as bad as it did," Lochte said.

While Phelps clocked 1 minute and 54.23 seconds to smash his previous world record by 0.57 seconds, Lochte finished third in 1:56.53, just 0.01 seconds behind silver medalist Laszli Cseh of Hungary. That was the same order of finish as the 400 individual medley, the race that began Phelps' amazing drive five days ago.

"Michael is unbeatable," Cseh said.

Cseh, who has won three silver medals behind Phelps, said he tried to swim faster in the opening 100 meters - the individual medley consists of legs of the butterfly, backstroke, breaststroke and freestyle - and he trailed by just .05 seconds after the backstroke.

But Phelps annihilated the competition with his breaststroke, building his lead to nearly a full second by the time he made his final turn and never letting up. Only one of his four individual victories has been decided by less than 1.89 seconds.

Even after another sensational swim, though, Phelps was not done. He quickly returned to the pool and swam the second-fastest qualifying time in a semifinal heat of the 100 butterfly, his final individual race of the meet in which he said he needs to swim a faster opening 50 meters to have a chance at the gold.

"I literally had about two minutes" to make his final preparations for the semifinal, he said. "I knew it was a tight turnaround, and the only thing I wanted to do today was win my heat in the 100 fly and get a center lane [for the final], and I did that. Hopefully, it will set me up for something good for tomorrow."

mcl@sltrib.com