Marko Grujic became Jürgen Klopp's first signing as Liverpool manager after sealing a move from Red Star Belgrade on January 6 2016.
Grujic's football education began in the Red Star academy, where he spent eight years learning his craft before making a first-team debut against Vojvodina at the age of 17 in May 2013.
In 2014, he was sent out to Serbian First League side FK Kolubara on loan, and picked up four months' worth of valuable experience before returning to his parent club.
Back in Belgrade, the midfielder established himself as a first-team regular over the course of the 2014-15 season, as he and his teammates claimed a second place in the Serbian Superliga.
Grujic's progress was recognised with a place in his country's squad for the FIFA U20 World Cup last summer, and he played a key role in their eventual victory in the competition, making five appearances in the finals.
A change of manager at Red Star prior to the new season kicking off then saw the his importance grow domestically, with Miodrag Bozovi placing faith in the youngster by putting him in central midfield.
Despite his tender years, Grujic has evidenced an ability to control matches with his physical presence and dictate play during an incredible start to the 2015-16 campaign.
Grujic signed off from Red Star Belgrade in style as he helped the side win the title in his final season. He was also voted into the SuperLiga Team of the Year for his contribution to Red Star's runaway victory.
Grujic started life at Anfield in 2016-17 and made eight appearances in an injury disrupted campaign.
In January 2018, Grujic joined Championship side Cardiff City on loan until the end of the season and played a big part as Neil Warnock's side achieved promotion to the Premier League.
Grujic was then awarded a place in the Serbia squad for the 2018 World Cup finals and signed a new long-term contract with Liverpool in August 2018, before joining Bundesliga club Hertha BSC on a season-long loan deal.