The recently concluded 2020-21 Premier League season was not short on drama, especially in the case of Liverpool. There were highs, lows, and everything in between during this roller-coaster of a campaign.It was the first time Liverpool had entered a Premier League season as Champions. But the past nine months were so far removed from The Reds' title-winning surge in 2019-20. This season represented some of the worst luck a top team has ever faced, bringing about some unprecedented challenges.Additionally, most of the season played out without fans in stadiums due to the COVID-19 pandemic. This carried forward from the previous season too, as Jurgen Klopp and his boys were not able to celebrate their monumental title win with the fans.Regardless, this season ended up being salvaged. But how did The Reds go from Premier League Champions to being content with a top four finish? Let's take a look at the draining season they had to endure.Here is a review of the insanity that was Liverpool's 2020-21 Premier League campaign, broken down into six stages.#1 A good start before disaster strikes (twice) for Liverpool⚽️ S U P E R S A D I O ⚽️#CHELIV pic.twitter.com/u7JvwgCUiD— Liverpool FC (@LFC) September 20, 2020This season began with the utmost optimism, with Liverpool aiming to retain their Premier League crown. They looked good value for it too. The Reds enjoyed a perfect start after winning the first three games of the season.The opening day saw Mohamed Salah score a hat-trick to ensure victory over a spirited Leeds United in their first game back in the top flight after 16 years away. The 4-3 win was a sign of the turbulence that was to come for Liverpool. They did coast to strong victories over Chelsea and Arsenal next, though.Sadio Mane showed some early season form, with three goals from those two games. Meanwhile, the signings of Thiago Alcantara and Diogo Jota further lifted the spirits at Anfield. The latter got off to the perfect start as he netted in the 3-1 win over Arsenal. Nobody could have predicted what came next.Liverpool suffered a freakish 7-2 defeat at Aston Villa, with their high defensive line being punished to no end. A couple of key absentees proved crucial, but that was barely the start of an incredibly troubled season in that respect.Could easily be an PCL injury this... really hope it isn’t. Really poor challenge. #EVELIV pic.twitter.com/kwMynyO0Vu— Samantha Quek (@SamanthaQuek) October 17, 2020The Reds' capitulation at Villa Park seemed nothing more than an anomaly, but their next game would have a lasting effect on the season. The Merseyside derby at Goodison Park saw Virgil van Dijk injure his knee following a poor challenge from Jordan Pickford. That was the end of the Dutchman's season.Liverpool were held to a 2-2 draw with Everton that day. A last-gasp Jordan Henderson winner was ruled out for a debatable offside by VAR. Thiago was also injured during the derby. However, van Dijk's injury would prove pivotal over the next seven months. His influence and control were irreplaceable.