WIMBLEDON, England — Something of a tennis extraterrestrial will alight Friday on Centre Court. It will be a male American in a Grand Slam semifinal, and that will be a first in these 2010s. It will have come, of course, under suboptimal circumstances.

Sam Querrey, a 29-year-old Californian who didn’t reach a Grand Slam quarterfinal until Wimbledon 2016, but kept plugging through his 37 Grand Slams before that, will become the first American male Grand Slam semifinalist since Andy Roddick in 2009. Like Roddick, whose masterful semifinal then against Andy Murray featured four tight sets, Querrey sent the Centre Court locals to murmuring and then to resignation Wednesday, shooing the British two-time champion from the Wimbledon quarterfinals, 3-6, 6-4, 6-7 (7-4), 6-1, 6-1.

Unlike Roddick, whose quarterfinal then was a hard, five-set slog with Lleyton Hewitt, Querrey had to perfect two other hard arts: forgetting his own grotesque shot, and taking advantage of a glaringly infirm opponent, Murray, who grabbed his shrieking left hip.

“American tennis isn’t that bad,” Querrey said with a near-wink, referring to four top-30 players from a country that doesn’t tend to bask in statistics such as “four top-30 players.” With the proper distinction of having plucked the No. 1-ranked player and defending champion from consecutive Wimbledons – Novak Djokovic in 2016, Murray in 2017 – Querrey will find an opponent who, in that great maze of past brackets, beat Querrey in a 17-15 fifth set in their previous Wimbledon encounter in 2012.

That would be sixth-ranked Marin Cilic, who edged past Gilles Muller, the Luxembourger who in the previous round conquered Rafael Nadal, 3-6, 7-6 (8-6), 7-5, 5-7, 6-1. Djokovic and Tomas Berdych succeeded that match on Court No. 1, and within a set-and-change, Wimbledon had another stunner. Djokovic, citing an elbow injury that has bedeviled him for 18 months but flared on Wednesday, retired trailing 7-6 (7-2), 2-0, and said, “I haven’t felt this much pain since I’ve had this injury, so it’s not a good sign.”

The Big Four, who had looked like they might just fill the semifinal brackets again, had dwindled to one, and that one, Roger Federer, found himself unbeaten in 13 sets and alongside players ranked Nos. 6, 15 and 28, after Federer wreaked a 6-4, 6-2, 7-6 (7-4) reversal on Milos Raonic, the Canadian who ousted Federer last year.

“I think he’s mentally sharper and I think he’s moving better,” Raonic said of Federer, soon adding, “You can see there’s not much doubt in his mind.”

For many a 35-year-old athlete, mental sharpness and better moving can stem from hiatuses, and recent history has found Federer in two of them: six months at the end of 2016 to heal, and 10 weeks in the spring of 2017 to avoid the common horror of clay.

“This year I’m just a normal tennis player again when I can focus on tactics,” the reigning Australian Open champion said. “I think that’s the difference. I’m playing very well. I’m rested. I’m fresh. I’m confident, too. Then great things do happen. Confidence is a huge thing.”

It is that, and it seemed to depart Murray at the hip, a subject which had only simmered as he combed through four opponents with one lost set. The two-time and defending champion even appeared he might hold on Wednesday when he weathered a third-set tiebreaker in which Querrey sprinkled four missed returns around a shocking human error and concluded that “it wasn’t the cleanest ‘breaker for me.”

When Querrey’s overhead – while trailing 2-1 – rocketed off his racket and slammed promptly into the net, the Centre Court audience conducted a brief gasp-a-thon. But from there, Murray spent the last 14 games in pain.

His movement, so essential to his top-rung level of prowess on tour, grew compromised. His challenges on line calls were so hopeless as to resemble cries for help. He resorted understandably to drop shots, which Querrey began to read, track down, fling back and follow with overheads that sang. With Murray’s pain obvious, Querrey looked every bit of a seasoned 29 years old by ignoring that truth, a tennis knack that has eluded many through the years.

“You try not to look at the other guy,” he said, “and literally just focus on what you do.”

He just focused especially when contorting his 6-foot-6 frame into serving. “The end of the fourth set and the fifth set, felt like he hardly missed any first serves,” Murray said, a guess seconded by the statistics, with Querrey nailing 22 of 32 through the closing two sets. Of his 32 service points after the third set, he won 28. Further, Murray noticed that Querrey has upgraded his comfort at the net where, Murray said, “He’s a big guy up there.”

Soon enough, Murray fielded a question about the “first U.S. player” in a major semifinal in the 2010s.

“Male player,” said Murray, ever the opposite of misogynist.

“I beg your pardon?”

“Male player,” Murray repeated.

Having walked out after the last of Querrey’s barrage of fourth- and fifth-set aces, Murray would have lost his No. 1 ranking if Djokovic had won this Wimbledon. That will not happen. Djokovic, who became the first player since 1969 to win four straight Grand Slams, has come to demonstrate what a toll that might exact. Here are his five Grand Slams since the 2016 French Open: third round, final, second round, quarterfinal, quarterfinal.

The reshaping of his reality began, of course, with Querrey, who stood No. 41 here last year and some ranking he doesn’t know this year. Asked to describe himself given this highest perch of fame, he said, “I’m ranked 26, pretty good grass-court player, that’s it.”

He’s ranked 28th but probably feels like 26th. By toughing out a five-set, two-day win over No. 10-ranked Jo-Wilfried Tsonga in the third round, Querrey even did some of his own dirty work clearing out the quarter of the draw through which he has proceeded, all the way to walloping a ball skyward to celebrate what he called “a really big deal.”

Beating Murray is always exactly that.