Rafael Nadal is a creature of fierce ritual and particular habits, with everything from the position of his water bottle in relation to his chair to the way he sprints to the baseline after every warm-up.
Muller puts his delayed emergence down to a 2013 elbow injury that nearly threatened his career and kept him off the courts which allowed him to work on his fitness and other aspects of his game.
Nadal had made serene progress through the draw until he faced Muller who stunned him by taking the first two sets in 74 minutes. I had a couple match points. "Yeah, somehow in the end I made it".
"I just tried to hang in there", said Muller of his epic battle with Rafa.
The clash between the five-time Wimbledon victor and the 20-year-old French Open champion provides one of the most intriguing matches of the quarter-finals.
He was favored to beat Muller, but he came up short on Monday. And he'd only reached a Grand Slam quarterfinal once before, at the 2008 U.S. Open.
"It's true that I played some good matches, but the same time is true that I didn't want to lose that match".
But 34-year-old grass court specialist Muller represents an altogether different challenge with his old-school serve-and-volley style that so bamboozled the Spaniard 12 years ago.
"I made a couple of mistakes that made me then play all the time against the score - and that's so hard against a player like him".
In the fourth, Nadal won a staggering 15 of 16 first serve points, a percentage of 94.
The match ended 15-13 in the fifth set and was the longest match of the tournament and indeed the best so far. He will have to wait a day to find out who he will play, though, as the match between second-seed Novak Djokovic and Adrian Mannarino was pushed to Tuesday because of darkness.
Nadal's departure truly opens the door for defending champion Murray, who along with Federer advanced in straight sets. Juxtapose that with this upset, in which Nadal will rue his 2-of-16 break point conversion rate, but has nothing to be ashamed of regarding a career-high 23 aces and a 77-17 ratio of winners to unforced errors.
For the entire fifth set up to the deciding game, both men held serve. Back in 2005, Muller defeated Nadal 6-4, 4-6, 6-3, 6-4 in the second round, although Nadal had won their most recent meeting in the 2011 third round.
Nadal threatened multiple breaks when they were tied at 9-9 with Muller serving.
Muller continued to stand the test of an enemy who would overwhelm others but struggled to keep up with his serve.
Now Muller will go on to face Marin Cilic in the quarterfinals, while Nadal is left watching from the Wimbledon sidelines for the sixth year in a row.
With the loss by Kerber, either Simona Halep or Karolina Pliskova will take over as the top-ranked player after the tournament.
Venus Williams, whose lukewarm Wimbledons earlier this decade suggested a fade, persisted with obliterating that notion on Monday. I was able to work out physically, and I got myself into the best shape I ever was. I mishit it. But I felt like I was doing the right things. "I have to see what the nuances are once the game starts, because you can't necessarily plan for those".
Ostapenko beat fourth seed Elina Svitolina of Ukraine 6-3, 7-6. She finally won by converting her eighth match point.
The seventh-seeded Russian will be playing in the quarterfinals at the All England Club for the fourth time, but the first since 2007. "He's won the title twice".
"I haven't really realised what just happened - it's just a great feeling", Mueller said at the end of the marathon match, that lasted four hours, 48 minutes.
Dane Caroline Wozniacki, seeded fifth this year, was dumped out by American 24th seed Coco Vandeweghe, while Russia's Svetlana Kuznetsova returned to the quarterfinals after a 10-year hiatus by beating Polish ninth seed Agnieszka Radwanska. Muller triumphed 6-4 4-6 6-3 6-4 on his way to the third round. But the 15-time Slam champion came roaring back after looking dead in the water.
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