how francis diafa went from sleeping at a tennis center to the u.s open semi-finals after stunning 22-time grand slam champion rafael nadal to reach the u.s open quarterfinal on monday francis diafo threw his racket on the floor and covered his face in amazement at it felt like a seminal moment in the 24 year old american's career a culmination of hard work and raw talent which has long been heralded as the potential future of men's tennis in the country now with tiafoe reaching the semifinals by beating andre rubella in straight sets wednesday he has recorded the best grand slam result of his career the achievement made all the more impressive given his humble beginnings.the crowd at arthur ashe stadium delighted in the play of tiafoe the first black american man to reach a u.s open semi-final since ash in 1972 and in a match where he didn't lose a service game to the world number 11 he couldn't let them down i feel so at home at courts like this this court is unbelievable you guys get so far behind me you know i want to play and want to give it my best i always find a way somehow on this court i always try to play great tennis and i have been he said in an on-court interview just after the math let's enjoy this one we got two more guys we got two more diaphos route into tennis has been in no ways traditional his parents met in the u.s after leaving sierra leone and had twins together franklin and francis dot their father constantifo started working at the junior tennis champions center in washington dc back in 1999 and eventually moved into one of its vacant storage rooms while working around the clock his two boys would sometimes stay with him sleeping on a massage table while their mother worked night shifts as a nurse the unusual gateway into the sport gave tiafoe an opportunity to start developing his skills and after beginning to train at the facility he didn't look back obviously i wasn't the wealthy kid or wasn't having all the new stuff or whatever but i was just living life i could play tennis for free the sport i loved he told cnn sport back in 2015 adding that he wouldn't change his upbringing for the world he was asked wednesday what message people should draw from his story i mean anybody can do it honestly obviously that's a cliche but i think if you are really passionate about something everybody's got a gift he said adding that his passion and obsession is tennis.thiefo and his twin brother franklin play in the fundraiser tournament in 2014. driven by the work ethic of his parents he won the prestigious orange bowl one of tennis most prized junior tournaments at 15 becoming the youngest boys singles champion in the tournament's history he joined a list of previous champions which included roger federer andy roddick ivan lendl jim courrier john mcenroe and bjorn borg it was a sign of things to come