There were high hopes that the 44-year-old wildcard would become the oldest woman to win a singles match at the All England Club since Martina Navratilova achieved the feat aged 47 in 2004, but Joint had other ideas.
The 20-year-old, who was not even born when Williams won the first seven of her 23 Grand Slam singles titles, blocked out all the hullabaloo surrounding her opponent's comeback to produce the most notable victory of her fledgling career.
Joint walked on to Centre Court on the back of winning just one match in her last 12 tournaments, but by the time she walked off, she was basking in the glory of delivering a brutal knockout blow to one of the greats of the sport.
Even when Joint was denied a chance to close out the contest after earning a match point in the second set tiebreak, she did not let that setback rattle her confidence or throw her off stride.
Around 45 minutes later, she was holding her arms aloft in victory after Williams ended one of the most talked-about comebacks in sporting history by swiping a service return long.
Joint will next play Filipino 29th seed Alexandra Eala.