The Reds signed the Scotland international in an £8m deal from Championship side Hull City in the summer transfer window.
Liverpool FC opted to sign Robertson from Hull following his impressive performances in the Premier League for the Tigers last term.
The 24-year-old scored one goal in 33 appearances in the Premier League last term to secure a move to Liverpool FC.
Robertson started the season as Jurgen Klopp’s second-choice left-back behind Spain international Alberto Moreno.
However, the Scottish defender seized his chance to shine in the Liverpool FC team following Moreno’s injury setback at the start of December.
Milner opened up about his initial reaction when Liverpool FC signed Robertson in last summer’s transfer window.
“I didn’t see loads and loads of him before. I knew of him, but you don’t really appreciate a player until you see him up close,” Milner told Liverpool FC’s website.
“With the quality he has going forward – the runs he makes and his quality into the box as well – he is a big player for us. The way we play, full-back is an important position.
“Coming to Liverpool, it’s not always easy to hit the ground running. Sometimes it takes you a season or 18 months to show your best form, so I’ve been impressed with how he has fitted in. But that’s credit to the environment that the boys make in the dressing room, and the club and the manager as well.
“Look at Mo [Salah] as well, coming in and hitting the ground running. I’ve changed clubs before and I know the first season is not easy, even if it is the same country.
“It is new surroundings and it’s not always easy to hit your form straight away. The boys who have come in have done brilliantly and that’s massive credit to them and also the boys in the dressing room.”
The Reds are in third place in the Premier League table and two points adrift of Manchester United in the race to finish as runners up to Manchester City.
Liverpool FC were 5-0 aggregate winners against Portuguese side FC Porto in the Champions League round of 16 earlier this month.
Klopp’s men will take on Premier League leaders Manchester City in the Champions League quarter-finals next month.
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