At the time, the left-back was just an ordinary footballer at best. So, when the Reds signed Robertson from Hull City for a transfer fee of €9 million back in the summer of 2017, we were slightly surprised.
Robertson had to bide his time when he first arrived at Anfield. Alberto Moreno was Jurgen Klopp's first-choice left-back at that particular point.
The Spaniard was performing well. But, an injury to Moreno opened up the door for Robertson.
The 27-year-old impressed immediately. The Scotland international made his Premier League debut for Liverpool against Crystal Palace at Anfield back in August 2017. Robertson was named Man of the Match.
The left-back's crossing and passing on the day highlighted that Liverpool possessed a player of real promise.
Since then, Robertson has not looked back. He is a defender by trade. However, Robertson has proven to be a real weapon in attack.
The full-back has scored six goals and registered 46 assists in 201 appearances for Liverpool. Robertson is basically an extra attacker out on the pitch for Klopp.
Former Liverpool full-back Fabio Aurelio has praised Robertson in the past for what he brings to the table.
The 42-year-old told the club's official website the following back in June 2020: "He's kind of the complete player because physically he's well capable of going forward and going back he defends very well.
"He's quick, so his one-v-one is good and defensively that's very important in the scheme Klopp plays. He goes forward very easily.
"One thing that calls my attention is that he's always improving, he's not comfortable in his situation being first-choice.
"You will see that in every game he plays as his last one, so that's courage."
Robertson is also a leader out on the pitch. The man is constantly demanding more from his teammates, which we absolutely love.
With that being the case, the defender was added to the club's official leadership group before the 2021-22 campaign got underway.
Klopp did predict back in 2018 that Robertson had the potential to become a leader within the club.
“Andy is a fantastic fella. He is a very smart and nice person. He can be a leader in the future, 100 per cent,” the German said, as quoted by The Liverpool Offside publication.
“He made big steps in the last one-and-a-half years since we worked together. That’s really cool. He has made big steps in the last four or five years since he started his career. So it’s a nice story.
“He is still young but he is a leader already and he will be even better in that in the future.”
Robertson has won four major trophies during his time at Liverpool. But, he still has time to win more silverware with the club.
Robertson is only 27 years of age, which highlights that his career is far from finished.
The left-back's contract does not expire until June 2026. Therefore, we do look forward to watching Robertson represent the Reds for many more years to come.
Robertson has stated that he would like to finish his career with Liverpool.
As quoted by Goal, the Scotland international told PLZ Soccer the following: "Look, my aim is to finish at Liverpool, and I’d love to finish at Liverpool, but I know how tough it is to keep playing at the highest level. Time will come to make that decision.
"Right now I’ve still got a good length on my contract, I want to stay here forever and I hope to retire here, but you know if I keep going and I feel fit and I feel healthy, but when you get into your 30s things change, but I’d love to retire at this club."
Providing Robertson keeps on performing, his wish may come true.