Among the many incredible achievements and records of Serena Williams' legendary tennis career, there is one that is even named after her. Twenty years to the day since Williams completed the 'Serena Slam,' tennis fans hailed the American great and celebrated the achievement and her tennis legacy.By winning the 2003 Australian Open, her maiden title at the Melbourne Grand Slam, Serena Williams recorded the unique feat of holding the title at all four Grand Slam singles tournaments at the same time. Leading up to the Australian Open, she had won all three of the previous Grand Slams held - the French Open, Wimbledon, and the US Open in 2002.The achievement of holding all four Grand Slams at the same time (not in the same calendar year) went on to be called the 'Serena Slam.'While Williams repeated the feat later in her career, from the 2014 US Open to 2015 Wimbledon, her first-ever Serena Slam remains very special to tennis fans, who celebrated its 20th anniversary on Wednesday."They don’t make tennis players like this anymore," a Twitter user wrote, referring to Serena Williams.Bri@4TheTennisThey don’t make tennis players like this anymore 🏾 twitter.com/espnw/status/1…espnW@espnW20 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 2324320 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 🏆 https://t.co/WfxG69d3sEThey don’t make tennis players like this anymore ☝🏾 twitter.com/espnw/status/1…@kp_official1 on IG@kp_official_1There will never be another twitter.com/espnw/status/1…espnW@espnW20 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 5520 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 🏆 https://t.co/WfxG69d3sEThere will never be another twitter.com/espnw/status/1…"Once in a lifetime superhero/shero....we'll never see anyone like her ever again; the aura, talent, energy, style....omg...... I'm really missing her," another fan expressed.Winnie Thomas @WinnieThomas11@serenapower_ @serenawilliams Once in a lifetime superhero/shero....we'll never see anyone like her ever again; the aura, talent, energy, style....omg...... I'm really missing her7@serenapower_ @serenawilliams Once in a lifetime superhero/shero....we'll never see anyone like her ever again; the aura, talent, energy, style....omg...... I'm really missing her❤️❤️👑🐐Here are a few more reactions from tennis fans to the two-decade anniversary of Williams' iconic 'Serena Slam':Brendan Churchill@BrenChurchilloh the glory days twitter.com/serenapower_/s…Luis.@serenapower_ On this day in 200321-year-old Serena Williams completes the 'Serena Slam' to win her first #AusOpen title after defeating Venus Williams 7-6(4), 3-6, 6-4.🥐38862📆 On this day in 200321-year-old Serena Williams completes the 'Serena Slam' to win her first #AusOpen title after defeating Venus Williams 7-6(4), 3-6, 6-4.🏆🥐🏆🍓🏆🗽🏆🐨 https://t.co/qax8c0EdbToh the glory days twitter.com/serenapower_/s…LTweets@LTweets2018It’s really been 20 years. twitter.com/serenapower_/s…Luis.@serenapower_ On this day in 200321-year-old Serena Williams completes the 'Serena Slam' to win her first #AusOpen title after defeating Venus Williams 7-6(4), 3-6, 6-4.🥐38862📆 On this day in 200321-year-old Serena Williams completes the 'Serena Slam' to win her first #AusOpen title after defeating Venus Williams 7-6(4), 3-6, 6-4.🏆🥐🏆🍓🏆🗽🏆🐨 https://t.co/qax8c0EdbTIt’s really been 20 years. twitter.com/serenapower_/s…No Malarkey@dynamitesz1@espnW Legacy. 5@espnW Legacy. ✨✨✨TicNation ☘️@PritchBurnerThat’s actually so crazy twitter.com/espnw/status/1…espnW@espnW20 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 2524320 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 🏆 https://t.co/WfxG69d3sEThat’s actually so crazy twitter.com/espnw/status/1…Tepid Sink Water@crystallineveeTwo calibres of the sport that we will never bear witness to again. twitter.com/espnw/status/1…espnW@espnW20 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 324320 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 🏆 https://t.co/WfxG69d3sETwo calibres of the sport that we will never bear witness to again. twitter.com/espnw/status/1…Nye the Songwriter Guy ✍🏾🔥@nyethesongwrita@serenapower_ @serenawilliams Her FIRST “Serena Slam”3@serenapower_ @serenawilliams Her FIRST “Serena Slam”Really Rei@MzLuckyleftyThe BIGGEST! twitter.com/espnw/status/1…espnW@espnW20 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 124320 years ago today, Serena Williams defeated her sister Venus in the Australian Open final, giving her simultaneous possession of all four Grand Slam titles 🏆 https://t.co/WfxG69d3sEThe BIGGEST! 🐐 twitter.com/espnw/status/1…A look back at Serena Williams' first ever 'Serena Slam'Serena Williams celebrates with the 2003 Australian Open trophy.Quite interestingly, Serena Williams beat her sister Venus Williams in the finals of all four tournaments that formed the first ever 'Serena Slam' in 2002-03.The first of those tournaments was the 2002 French Open, in which the younger Williams sister beat Mary Pierce, Jennifer Capriati, and her older sibling Venus in consecutive matches to win her maiden French Open title and her second Grand Slam singles title. The next tournament was Wimbledon, where Williams did not drop a single en route to the first of her seven Wimbledon titles, beating Venus 7-6(4), 6-3 in the final.The two sisters then faced off in the final of their home Grand Slam, the US Open, with Serena again going on to win the tournament without losing a set. She beat Venus 6-4, 6-3 in the 2002 US Open final. Finally, at the 2003 Australian Open, she completed the first of two Serena Slams by winning a three-set thriller against Venus.