He's Tennys Sandgren. Even his name is intriguing. Playing for the first time in Melbourne at 26, the world No.97 hadn't won a match in his two previous main-draw appearances at the majors - and both those came courtesy of wildcards. Now his name features in the final eight alongside Roger Federer, Rafael Nadal, Tomas Berdych and Marin Cilic.

The reporter put it this way: "We were trying to find the last guy who made a grand slam quarter-final with less of a pedigree than you. We were struggling."

The Tennessee native, only the second debutant to reach the Australian Open quarter-finals in 20 years - alongside Alexandr Dolgopolov in 2011 - himself laughs at his incredulous progression.

"I definitely had a real pinch-me moment. Wow, this is hopefully real, you know. If I wake up now, I'm going to be real upset," Sandgren said, laughing.

But with new-found notoriety comes attention, perhaps unwanted. Sandgren's social media activity and political views have also been highlighted as his profile has risen.

He deleted 18 months' worth of tweets in the aftermath of his fourth round win over Austrian world No.5 Dominic Thiem.

Among the deleted tweets was one from November 2016 where Sandgren appeared to back the debunked Pizzagate online conspiracy which had linked Democratic presidential candidate Hillary Clinton to a supposed child sex abuse ring at a Washington pizzeria.

And earlier this month, he retweeted a video from white nationalist Nicholas Fuentes.

Grilled on his apparent support for the alt-right movement in the United States, Sandgren said he found some of the online content "interesting" but stressed that he did not support the movement.

"No, I don't. I don't," he told reporters. "I find some of the content interesting.

"But, no, I don't. Not at all.

"As a firm Christian, I don't support things like that, no.

"I support Christ and following him."

Sandgren turned pro in 2011. After his remarkable win Thiem over five gripping sets, the American his arms aloft after the 6-2, 4-6, 7-6 (7-4), 6-7 (9-7), 6-3 win in nearly four hours. His other vanquished opponents have included former champion Stan Warwinka.

Back to THAT name. It's handed down from his Swedish great-grandfather who had no connection to tennis. Wherever he goes he's constantly asked about it - to the point where now he uses a different name when ordering food.

"I say 'David' or something like that. I don't want to deal with the whole name thing when I get a coffee, especially first thing in the morning. I would prefer to get the caffeine, then I can maybe think about approaching the day first," Sandgren said after an earlier win in Melbourne.

"I don't hold a grudge of sheer anger at life because of my name. No, no, no. It's something unique and cool. It's just a part of who I am. I'm OK with that."

The American will meet one of the other two bolters to the final eight in Melbourne, South Korean Hyeon Chung, the emerging 21-year-old star who, stunningly, blew Novak Djokovic off the court in three tight sets in what was, fascinatingly, a Djokovic-like performance.

It's the most unlikely men's quarter-final at the majors in quite some time, adding fuel to the theory that the Federer-Nadal-Djokovic-Murray-Wawrinka stranglehold is slowly eroding (but nobody will be surprised if it's another Fedal special this Sunday night).

And one of Sandgren or Chung will join England's Kyle Edmund in the final four.

Sandgren got into tennis because of family influence. "My parents and my older brother played. You kind of want to do what your family does. They were on the court. I'm like, I want to be on the court, too.

"I think there was like a childhood moment where I had to pick shoes, either non-marking or marking shoes. The marking shoes were Spider-Man shoes. I'm like, well, I want the Spider-Man shoes. But I also didn't want to mark the court, I want to be able to play. I chose the generic, non-marking shoes," he remembers.

"It was kind of one of those moments where you choose your path, choose to do something, even at a young age."

But he's not the only member of his family to endure physical punishment during the Open, his charmed run also taking a toll on his mother, watching at home in the States.

She fell against a pool table and broke a rib while jumping up and down celebrating.

"I've got like a neighbourhood, core neighborhood group, with my mom. They watch a lot of my bigger matches. They'll go in the basement, put the match on the projector screen on the bottom," Sandgren said.

"They were jumping up and down, celebrating. She fell onto the pool table, cracked a rib. Whoops.

"I was concerned about it. She went to the hospital, thankfully. She's lying down, resting, watching some tennis and having a good time."

???

With the new scrutiny that came after his bolt from the blue, the American was happy to dispel any potential connections he had with "controversial figures" and defended his Christian beliefs.

"Look, who you follow on Twitter I feel doesn't matter even a little bit. What information you see doesn't dictate what you think or believe," Sandgren replied.

"I think it's crazy to think that. I think it's crazy to assume that. To say, well, he's following X person, so he believes all the things that this person believes, I think it's ridiculous.

"You can ask me about my beliefs on things, that's cool. But I think to lump in and say, You follow this person, so then wow, who are you? Ask me who I am. I'm perfectly fine answering those kinds of questions."

With AAP