But Phelps, with a big hand from three teammates, would not be denied. He eclipsed Mark Spitz's seven-gold performance at the 1972 Munich Games, an iconic performance that was surpassed by a swimmer fitting of this generation: a 23-year-old from Baltimore who loves hip-hop music, texting with his buddies and wearing his cap backward.
"I don't even know what to feel right now," Phelps said. "There's so much emotion going through my head and so much excitement. I kind of just want to see my mom."
Debbie Phelps was sitting in the stands at the Water Cube, tears streaming down her cheeks, her two daughters by her side. After getting his gold, Phelps quickly found his family, climbing through a horde of photographers to give all three of them a kiss.
Mom put her arm around his neck and gave him a little extra hug.
Her son sure earned it.
"The Beijing Olympics has witnessed the greatest Olympian of all time -- Michael Phelps of the USA," the announcer said as Phelps posed on the deck with his teammates.
Even though the Americans have never lost the medley relay at the Olympics, the latest win was hardly a breeze. When Phelps dived into the water for the butterfly -- the third of four legs -- the Americans were third behind Japan and Australia.
But Phelps, swimming the same distance and stroke that he used to win his seventh gold a day earlier, powered to the front on his return lap, passing off to Lezak with the Americans in front.
Australia's Eamon Sullivan tried to chase down Lezak and appeared to be gaining as they came to the wall. But Lezak touched in 3 minutes, 29.34 seconds -- Phelps' seventh world record in his personal Great Haul of China.
The Aussies took silver in 3:30.04, also under the old world record, while Japan held on for the bronze.
"Nothing is impossible," Phelps said. "With so many people saying it couldn't be done, all it takes is an imagination, and that's something I learned and something that helped me."
Phelps patted breaststroker Brendan Hansen on the head and threw his arms in the air after Lezak finished, though the Americans still had to wait a couple of tantalizing minutes for the official results to be posted. Aaron Peirsol swam the leadoff leg for the Americans.
Finally, it flashed on the board.
Gold medal No. 8.
On deck, a beaming Phelps slapped hands with his teammates and thrust his arms toward the Water Cube roof. The winning swimmers locked arms as if they were in a football huddle about to break for a play.
Phelps, who won five individual races and three relays in Beijing, couldn't stop smiling. He also gave a shout-out to those who helped him take down Spitz.
"Without the help of my teammates this isn't possible," he said. "I was able to be a part of three relays and we were able to put up a solid team effort and we came together as one unit.
"For the three Olympics I've been a part of, this is by far the closest men's team that we've ever had. I didn't know everybody coming into this Olympics, but I feel going out I know every single person very well. The team that we had is the difference."
Phelps won some races by ridiculously large margins, others with the closest of finishes -- most memorably, his seventh gold by one-hundredth of a second over Serbia's Milorad Cavic in the 100 fly.
He set seven world records and one Olympic record, doing a personal best time in every event.
"It's been nothing but an upwards roller-coaster and it's been nothing but fun," Phelps said.
After receiving his gold, Phelps received another award from FINA, the sport's governing body, as the best swimmer of the meet.
Make it the best ever.