A day after etching his name alongside Mark Spitz and Carl Lewis with gold No. 9, Phelps claimed the record all to himself when he won the 200-meter butterfly Wednesday morning. He later led the American team to gold in the 800-meter freestyle relay.
Phelps had a problem with his goggles - but that didn't keep him from touching first during the butterfly.
He's now all alone at the top, with three more chances to stretch his lead before he leaves China.
Phelps has trained in Ann Arbor, Mich., as part of Club Wolverine.
In the fly, his signature stroke, Phelps was second at the first flip, then pushed it into another gear, his long arms gobbling up huge chunks of water as he literally sailed along atop the surface. He touched the wall in 1 minutes, 52.03 seconds, breaking his mark of 1:52.09 from last year's world championships.
He barely smiled as he looked at the board, breathing heavily and hanging on the lane rope. Hungary's Laszlo Cseh really pushed it at the end, but settled for silver in 1:52.70. Japan's Takeshi Matsuda took the bronze in 1:52.97.
Phelps rubbed his eyes and said climbing from the pool, "I can't see anything." A pair of leaky goggles kept him from even seeing the wall as he finished.
Still, it was another gold and another record, taking Phelps halfway to his goal of beating Spitz's record of seven gold medals in a single games.
"My goggles kept filling up with water during the race," he said. "I wanted a world record, I wanted 1:51 or better, but in the circumstances not too bad I guess."
Everyone wanted to get a look at history, including the U.S. men's basketball team. Kobe Bryant, LeBron James and Carmelo Anthony were among those cheering on Phelps from poolside seats. James posed for pictures with Phelps' mom, Debbie.
Just to set the tone, three worlds records fell before Phelps even walked on deck.
But some say this year's swimming competition is rigged for record-smashing with what one critic called , reports CBS News correspondent Barry Petersen.
Advancements in the swimsuits, which are made to mimic shark skin, and variations in pool design may give these Beijing Olympians an advantage over athletes in previous games.
Phelps swam the leadoff leg of the 800-meter freestyle relay and helping the United States smash the old world record by 4.68 seconds.
Phelps, Ryan Lochte, Ricky Berens and Peter Vanderkaay led the entire race, winning in 6 minutes, 58.56 seconds. That bettered the old mark of 7:03.24 set by the U.S. at last year's world championships in Australia.
Russia took the silver in 7:03.70. Australia earned the bronze in 7:04.98.
Berens gushed over Phelps' performance, telling CBS' The Early Show that his teammate is "incredible. I mean, race after race, that
guy does it all."
In the semifinals of the 100 free, Australia's Eamon Sullivan and France's Alain Bernard played takeaway with the record Sullivan set two days earlier.
In the first heat, Bernard won in 47.20 to knock down Sullivan's mark of 47.24 from the leadoff leg of the memorable 400 free relay. That record lasted all of 2 minutes. Sullivan won the second heat in 47.05, setting up a thrilling showdown in Thursday's final.
"Records don't mean much," Sullivan said. "They don't win medals at the end of the day, unfortunately. But it gives me confidence that I can swim my own race under pressure."
American Jason Lezak, who chased down Bernard in the relay, advanced to the final with the sixth-best time, 47.98. The other U.S. swimmer, Garrett Weber-Gale, failed to advance.
Then it was Federica Pelligrini's turn. The Italian broke the mark she set a day earlier in the semifinals, winning gold in 1:54.82. The old record was 1:55.45.
Sara Isakovic of Slovenia claimed the bronze in 1:54.97, and China's Pang Jiaying thrilled the home fans by passing Katie Hoff on the final lap to take bronze in 1:55.05.
It was another disappointment for Hoff, who looked to be one of the big stories of the game when she qualified in five individual events - the same number as Phelps.
The 19-year-old American, who considers Phelps her big brother, has yet to match his success in the water. In her first two races, Hoff settled for a bronze and a silver, which look pretty good after she faded out of the medal hunt in the 200 free, finishing 0.63 behind Pang.