Serena Williams’ dominating run at the majors ended in a painful loss to American teenager Sloane Stephens.

After the biggest and most unexpected victory of her life, 19-year-old Stephens is headed to the semifinals of the Australian Open.

Williams hurt her back in the eighth game of the second set, slowing down her serve, restricting her movement and causing her obvious pain.

But Stephens kept her composure, blocking out the injury issue on the opposite side of the net and rallied for a 3-6, 7-5, 6-4 victory on Wednesday by far the most significant in her seven Grand Slams.

The gravity of it didn’t hit Stephens until she was warming down, and even then it was an unreal feeling.

“I was stretching, and I was like, ‘I’m in the semis of a Grand Slam.’ I was like, ‘Whoa. It wasn’t as hard as I thought.’ But it’s pretty cool,” she said. “To be in the semis of a Grand Slam is definitely I say a good accomplishment. A lot of hard work.”

After winning her first Grand Slam quarterfinal, Stephens next plays defending champion Victoria Azarenka.

Murray through

Andy Murray reached his fourth consecutive semifinal at the Australian Open with a dominating 6-4, 6-1, 6-2, defeat of Jeremy Chardy.

Murray motored to a two-set lead over Chardy, at one point winning 10 of 11 games to reach 3-0 in the third set.

The Scot overcame a niggle, as he lost serve for 5-2 through a double-fault. But he broke Chardy straight back to earn victory in just under two hours with eight breaks of the Frenchman.

“Today was the best I’ve played,” said Murray. “I’ve struggled a bit in the last few rounds. “I needed to come out sharp from the start since Jeremy has had such a good tournament.”

“When I got up, I was like, ‘Look, Dude, like, you can do this.’ Like, ‘Go out and play and do your best,” Stephens said.

It wasn’t until after losing the first set and being broken in the first game of the second that she really convinced herself she could.

“I was like, ‘Hmm, this is not the way you want it to happen. But you just fight and just get every ball back, run every ball down, and just get a lot of balls in play, I think you’ll be OK.’

“From then on I got aggressive, started coming to the net more, and just got a lot more comfortable.”

She started hitting winners, cutting down on the errors, and pushing the injured Williams around the court.

Williams walked around the net to congratulate Stephens, who then clapped her hand on her racket and waved to the crowd, a look of disbelief on her face.

Stephens has said she had a photo of Williams up in her room when she was a child, and had long admired the Williams sisters.

“This is so crazy. Oh my goodness,” Stephens said, wiping away tears in her post-match interview. “I think I’ll put a poster of myself (up) now.”

Azarenka sails

Azarenka overcame some early jitters to beat Svetlana Kuznetsova 7-5, 6-1 in the earlier quarterfinal match at Rod Laver Arena.

After dropping serve in a long fourth game that went to deuce 10 times, Azarenka recovered to dominate the rest of the match against Kuznetsova.

Azarenka’s American rapper friend, Redfoo, returned from a concert in Malaysia to attend Wednesday’s quarterfinal match.

Wearing a red sleeveless T-shirt that read “Keep Calm and Bring Out the Bottles,” the name of his next single, Redfoo stood, clapped and yelled “Come on, Vika!” during the tight first set.

Asked if it helped to have her No. 1 fan wearing a keep calm logo, Azarenka said “I was looking more at the part that says ‘Bring out the bottles.’”

Of her game, she added, “I’m just glad I could produce my good tennis when it was needed.”

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