LONDON >> Seventh at the turn, an Olympic champion at the end.

For the 17th time.

What a way for Michael Phelps to go out in the final individual race of his career.

With those long arms whipping through the water, Phelps was next-to-last when he touched the wall at the far end of the pool in the 100-meter butterfly but in a familiar position at the end Friday — his name atop the leaderboard, a smile on his face, another gold medal around his neck.

Phelps claimed his third gold of the London Games and 17th of his career, adding to an already absurd record total that could be twice as much as anyone else by the time he swims the final race of his career, the 4×100 medley relay Saturday night.

The Americans are huge favorites in a race they never lose, and it’s unfathomable to envision the Phelps era ending with anything less than a performance that puts him atop the podium one last time.

In what might be viewed as a symbolic changing of the guard from America’s greatest swimming star to the next big thing, 17-year-old Missy Franklin set a world record in the 200 backstroke, her third gold in London, just minutes before Phelps took center stage at the Olympic Aquatics Centre. Another American teen, 19-year-old Elizabeth Beisel, claimed the 200 back bronze.

And right after Phelps was done, 15-year-old Katie Ledecky — the youngest member of the U.S. team — nearly broke the world record to win gold in the 800 freestyle, denying Britain’s Rebecca Adlington a repeat before her home fans. Adlington settled for bronze in a race Ledecky dominated from start to finish.

But no one has dominated like Phelps, who increased his career overall medal total to 21.

In the 200 backstroke, Franklin clocked 2 minutes, 4.06 seconds, 0.75 quicker than the mark set by Kirsty Coventry of Zimbabwe at the 2009 world championships in Rome in a now-banned bodysuit.

It was the seventh world record of the games.

Anastasia Zueva of Russia touched in 2:05.92 to take the silver medal and Beisel of the United States finished in 2:06.55 to take bronze.

The youngest member of the U.S. swim team, Ledecky narrowly missed a world record in the grueling 800 free, falling off pace on the last lap and finishing in 8 minutes, 14.63 seconds.

Mireia Belmonte Garcia of Spain touched in 8:18.76 to take the silver medal and Adlington finished in 8:20.32 for bronze.

Adlington set the world record of 8:14.10 at the 2008 Beijing Games.

Florent Manaudou of France won the 50-meter freestyle on Friday.

The brother of former 400 free champion Laure Manaudou clocked 21.34 seconds in the one-lap race. It was France’s fourth swimming gold of the games.

Cullen Jones of the United States touched in 21.54 to take the silver medal and defending Olympic and world champion Cesar Cielo of Brazil finished in 21.59 to take bronze.