From sleeping on a tennis club floor to the quarter-finals of the Australian Open – it was no surprise that Frances Tiafoe was overwhelmed by his victory over Grigor Dimitrov.

The American made his latest statement at Melbourne Park with a 7-5 7-6 (6) 6-7 (1) 7-5 win against the 20th seed.

It was a dream 21st birthday present for the man from Maryland and his thoughts immediately turned to where he has come from as he struggled to hold back the tears.

"It means the world," he said. "I worked my ass off man. I told my parents 10 years ago I was going to be a pro, I was going to change my life and their life. Now I'm in the quarters of a slam. I can't believe it."

Tiafoe's parents were immigrants from Sierra Leone struggling to make a life in the United States.

The work ethic of father Constant stood out when he took a job constructing a tennis centre, and he was given a job as head of maintenance when it opened.

Constant was allowed to sleep in the spare office and, with the centre in a much safer area than the one-bedroom apartment the family shared with relatives, his twin sons Frances and Franklin were soon spending most of their time there, too.

Watching the coaches teach the rich kids gave young Frances an early tennis education, which he put into practice whenever the courts were free, and soon it became clear the prodigy was not a child who went home to a comfortable house but one who slept on the floor.

"My academy, a ton of wealthy guys," he said. "You got cats rolling in there with chauffeurs, all that.

"I'm not saying you can't make it if you grew up from a wealthy situation. A ton of people have. But obviously that gave me an incentive, a reason to give, a reason to work every day, understand why you do it."

The reason was a better life for his family. In 2017 he bought mother Alphina a home in Maryland, while his father lives in a flat in Orlando.

"I obviously wasn't a normal tennis story," he said. "The beginning of my career, I was playing for them, trying to do everything for my family. Obviously now I put them in a great place. Now I'm trying to do it for me."

Tiafoe has only been to Sierra Leone once, on a trip with his mother and his brother when he was seven or eight.

"It was more my pops who wanted me to go there," he said. "Thought I was getting spoiled. He said, 'You need to get you learned something, get you cultured'. I came back definitely thinking different, came back appreciating everything.

"People were talking about me and Franklin over there.

"We had people (in America) making fun of us for wearing PE shirts to play tennis, holes in our shoes. They said, 'You guys don't even understand. You guys got American passports, got the opportunity to do something great. Go and do it'.

"After that, it put things in perspective for me. I ain't ever acting spoiled ever again."

After upsetting fifth seed Kevin Anderson in the second round, Tiafoe came from two sets to one down to see off Andreas Seppi in round three, and his clash with Dimitrov was another tight affair.

Tiafoe won the second-set tie-break from 3-6 down and then lost the third from a break up, with his energy levels beginning to become critical.

He had several chats with the trainer, saying later: "I was just trying to stay alive, man."

For a pick-me-up he drank juice from a jar of pickles. "I'm talking straight up, just downing it. Tasted terrible. I'm feeling terrible right now."

Tiafoe must now try to recover for the most physical test in tennis when he faces Rafael Nadal on Monday.

"I'm so excited to play Rafa," he said. "We're going to have some fun, going to have some long rallies."