LONDON - Michael Phelps savored one last golden moment Saturday, capping his remarkable Olympic swimming career with an 18th gold medal in the final event in the Aquatics Centre competition pool.
"It's tough to put into words right now," Phelps said. "I did everything I wanted to do.
"I finished my career the way I wanted to, and I don't care what anyone says, if I can say that, it's all that matters."
With the US men unbeaten in the 4x100m medley relay in Olympic competition, the race was a coronation for the man Serbian swimmer Milorad Cavic called "the king".
But breaststroke star Kosuke Kitajima added some drama to the occasion, seizing a narrow lead for Japan by the time Phelps dived in for the butterfly leg behind US backstroker Matt Grevers and breaststroke swimmer Brendan Hansen.
Takeshi Matsuda maintained Japan's advantage at the 50m mark of the fly, but Phelps delivered a classic final lap to seize the lead for the Americans and 100m free gold medallist Nathan Adrian was untouchable in sealing the victory in 3:29.35.
"It is one of the funnest ways to do it," Phelps said of closing out his career with a relay.
"Being able to step up with these four guys and continue this streak is important to us.
"I just said before we went out, we've got to want to win, let's just go out and do it," Phelps said.