Just 24 hours after Rafa Nadal's unlikely demise, Benneteau sent shockwaves of equal magnitude around the All England Club as he destroyed Federer during the first two sets with ferocious forehands, belting backhands and audacious reflex shots.
When the Frenchman stood two points from victory in the 12th game of the fourth set, and again in the tiebreak, it seemed as if Federer's incredible streak of reaching 32 consecutive Grand Slam quarter-finals or better would end on the Swiss's much-loved Centre Court arena.
But fraying nerves is not the sign of a champion who has won a record 16 Grand Slam titles, including six Wimbledon crowns, and he did not flinch once as he withstood Benneteau's onslaught to steer the match into a fifth set.
Once there, the zing suddenly went out of Benneteau's previously supercharged legs.
He appeared like a man walking through treacle as he limped between points and even called on the trainer to massage his exhausted limbs back to life but it was to little avail as Federer raced through the final set.
When the Swiss third seed brought up three match points and was waiting to deliver his final serve, a distraught Benneteau could not even face reality as he covered his eyes with his hand and turned his back to the net.
But he could not delay the inevitable forever and the man who had come so close to pulling off one of the biggest ever shocks surrendered his Wimbledon hopes by paddling a tired shot into the net.
It left the Swiss master to savour a near escape, 15,000 anxious Centre Court fans to sigh in relief and a dejected Benneteau to contemplate what might have been.
"Oh my God, it was brutal. Bit of luck in my side maybe. I fought till the very end. I tried in the third, fourth and fifth just to stay alive - in the fourth it was so close," a hugely relieved Federer said after surviving the three hour, 34 minute test played out under a closed roof despite the absence of rain.
"Julien was playing amazingly. When you're down two sets to love you have to stay calm even though it's hard because people are freaking out.
"You obviously don't have many lives left out there and you just try to play tough and focus point to point.
"Indoors is not what we're quite used to on grass and I'm happy I got this one out of the way," added the third seed.
Federer has long held the belief that best-of-five-set matches favour the top players as "a spell or two or five bad minutes" could be costly on grass.
On Friday, Federer, who is bidding to become the first 30-something man since Arthur Ashe in 1975 to lift the Challenge Cup, backed up his theory.
At 6-5 up in the second set Federer edged to within a point of levelling the match to one set all. Three times he held set point and three times he watched Benneteau go for broke.
Benneteau's blazing forehand sent the chalk flying on the first set point, his ace whizzed past Federer's ears on the second and the Frenchman drew gasps of admiration as he produced a jaw-dropping dropshot on the third.
Surviving a game that had stretched to seven deuces and three break points energised Benneteau and he roared through the tiebreak 7-3, leaving Federer teetering on the edge.
But just as he had done on seven previous occasions, the Swiss dug himself out from a two-set hole to spark jubilant celebrations among his Centre Court fans, many of whom who had turned up wearing an array of whacky earrings, hats, dungarees and even sunglasses monogrammed with his signature RF initials.
"Mentally he's a rock. He's two sets down and he doesn't show anything," said Benneteau, who admitted for a fleeting moment before the start of the fifth set he thought he could following in the footsteps of Nadal's conqueror Lukas Rosol.
"It was a magic moment, for sure but (it lasted) just like one second."
Next up for Federer is a match against fellow veteran Xavier Malisse.
The Belgian, a semi-finalist at SW19 10 years ago, was visibly moved after winning a five-set epic against Spanish 17th seed Fernando Verdasco, eventually triumphing 1-6 7-6(5) 6-1 4-6 6-3.
Novak Djokovic survived the shock of losing the first set to beat Radek Stepanek 4-6 6-2 6-2 6-2 and reach Wimbledon's last 16.
When 33-year-old Stepanek, delighting the crowd with old-fashioned serve and volley tennis and slightly eccentric mannerisms, took the first set there were murmurs around the same Centre Court which was shaken to its foundations by Lukas Rosol's barrage of winners against Rafael Nadal the previous evening.
However, Serb Djokovic never looked unduly alarmed under the closed roof and once he began being more aggressive he quickly began to dominate against the oldest survivor in the men's draw.
The top seed broke in the first game of the second, third and fourth sets to re-establish control and raced to victory with a battery of laser-guided passing shots that often left the net-rushing Stepanek swishing at thin air.
Despite conceding his first set of the tournament, Djokovic ended the match against Stepanek like a well-oiled machine and clearly enjoyed himself as he booked a weekend off before a last-16 clash with compatriot Viktor Troicki.
Troicki ousted the 15th seed Juan Monaco in straight sets 7-5 7-5 6-3 to set up the showdown.
"When you're playing that well you want to stay on the court," the world number one said.
"He was very aggressive so it was a tough match, but I think I played the second, third and fourth sets very well.
"He's a very tricky player, very experienced, and one of the few players who comes to the net. I love these conditions under the roof. I'll enjoy a couple of days off now - a spot of golf, and then try to improve my game for the next challenge."
Sam Querrey completed his second round match against Wimbledon dark horse Milos Raonic, winning 6-7(3) 7-6(7) 7-6(8) 6-4.
There was very little to separate the American and the 21st seed, but Querrey won crucial points in the tie breaks to put the match beyond doubt, and hit 21 aces to advance in a match carried over from yesterday.
“Usually I’m pretty calm and collected after a win or loss, but, yeah, kind of let it out there a little bit at the end. It just felt good," said Querrey, who will improve his ranking from 64th with this run, which now pits him against 16th seed Marin Cilic.
31st seed Florian Mayer had to dig deep to fend off the spirited challenge of Poland's Jerzy Janowicz, eventually winning 7-6(5) 3-6 2-6 6-3 7-5.
Richard Gasquet will meet Mayer next, having looked assured in beating 12th seed Nicolas Almagro 6-3 6-4 6-4 on Court One.
Mikhail Youzhny ended the challenge of eighth seed Janko Tipsarevic in four sets with an impressive performance.
The Russian, himself seeded 26 at SW19, will next play Denis Istomin, conquerer of Colombian Alejandro Falla 6-3 6-3 3-6 7-6(5).