The band's three surviving members - singer Robert Plant, guitarist Jimmy Page and bassist-keyboardist John Paul Jones - were joined by the late John Bonham's son Jason on drums.
And it was the newest member of the band that was given the honor of kicking off the sold-out benefit show, pounding out the beat before the others joined in on a near-perfect "Good Times Bad Times."
After the lights went down at the O2 Arena, newsreel footage of the band arriving in Tampa, Fla., for a 1973 performance was projected onstage. Then Bonham jumped in, soon to be joined by the rest.
They followed that with "Ramble On," and with it destroyed all rumors that the 59-year-old Plant could no longer reproduce his trademark wail.
With his button-down shirt mercifully buttoned up, Plant roamed the stage belting out hit after hit, rarely giving his critics anything to work with.
But Page showed he still has the touch as well. Besides ripping out his patented riffs all night, he put the spotlight on himself when the band played the bluesy "In My Time of Dying."
With his left hand moving freely up and down the neck of his guitar and the metal slide wrapped around one of his fingers, Page effortlessly played a song that's not easy to master.
Page and Plant later combined to open "Nobody's Fault But Mine," a song that starts with another classic Page riff and then gets help from Plant mimicking the same sounds.
Still, it was Bonham who may have been the star of the show. At 41, he is older than his father was - 32 - when he choked to death on his own vomit in 1980.
Bonham's flawless performance and driving beat even made the other members of the band watch in awe at the end of "Black Dog."
After "The Song Remains the Same," Plant screamed: "Jason Bonham, drums! Come on!"
The 16-song set list produced few surprises. They did many of the songs expected, such as "No Quarter" and "Trampled Under Foot," and the entire show lasted a bit more than two hours, mainly because of encores "Whole Lotta Love" and "Rock and Roll."
The band also played "For Your Life" live for the first time.
"It's quite peculiar to imagine ... to think about creating a dynamic evening choosing from 10 different albums. There are certain songs that have to be there, and this is one of them," Plant said in introducing "Dazed and Confused."
When Page's solo started midway through the song, many in the audience were wondering whether the guitar virtuoso would resort to his old tricks.
But after only a few seconds, the 63-year-old Page turned his back to the crowd and walked nonchalantly toward his amp. Once there, he pulled a cello bow off the top, and the fans again went wild.
They followed that with "Stairway to Heaven," the band's staple song, which many hardcore fans were hoping would be dropped from the set.
But the crowd still loved it, with many standing to dance as Page played on his double-necked guitar.
A few lighters even popped up, but they were mostly replaced by digital cameras.
Plant may have struggled a bit on the early verses - his voice a tad raspy - but it was hardly reason to believe the band wasn't ready for anything.
Fans are hoping to get to hear them do it again, and soon.
Though this show is supposed to be one-time event, there have been rumors that if all went well, it would kick off a world tour.
Plant seemed to play down those rumors, saying he plans to tour with bluegrass star Alison Krauss, but Monday's performance will only add to the fervor of the fans to see them play more gigs.
"The whole idea of being on a cavalcade of merciless repetition is not what it's all about," Page told The Sunday Times leading up to the performance.
The show was Led Zeppelin's first full set since 1980. Robbed of "Bonzo's" pulsing drums, the band decided it couldn't go on and split up on Dec. 4, 1980 .
Tickets for the show, a benefit for the late Atlantic Records founder Ahmet Ertegun, were won in an Internet lottery. Proceeds are to go to the Ahmet Ertegun Education Fund, which provides scholarships to universities in the United States , Britain and Turkey .
"Hey Ahmet, we did it!" Plant screamed after "Stairway."
Monday's concert wasn't the first Led Zeppelin reunion. The band played together in 1985 at Live Aid, and joined forces again three years later - with Jason Bonham on drums - to play at the 40th anniversary concert for Atlantic Records.
At their Rock and Roll Hall of Fame induction ceremony in 1995, they teamed up with other musicians for another short set.
The show was originally scheduled for Nov. 26, but was postponed until Monday because Page injured the little finger on his left hand.
There were several opening acts rotating across the stage, mainly hosted by former Rolling Stones bassist Bill Wyman.
Paul Rodgers, Keith Emerson and Foreigner got the biggest cheers.
Plant said he was told that people from 50 countries made their way to London for the show.
"I can't believe people would come from 50 countries for that," Page said after pointing out a banner in the crowd that read "Hammer of the Gods."
They came, and they saw a show that hopefully won't be the last.