Jürgen Klopp has sounded an Andy Robertson warning.

The Scotland captain’s Liverpool career truly sprung to life almost 12 months ago, when an injury setback for Alberto Moreno allowed the former Hull City left-back to break into the first team.

It was a chance Robertson clenched with both hands and has never let go of. Of the 52 competitive games the Reds have played since the beginning of December 2017, the No.26 started 43.

Another marauding display at Watford on Saturday saw the 24-year-old defy the 89 minutes of action in his legs to launch a phenomenal counter-attack that led to a third, and victory-sealing, goal for Roberto Firmino.

Ask Klopp, though, and there is more to come from Robertson. Much more.

“I don’t compare seasons, to be honest, but I’ve known Robbo now for one-and-a-half years and I feel that he’s at 75 per cent – maybe less – of what he can do,” the boss told Liverpoolfc.com.

“There’s a lot of potential still. But it’s all good. He improved a lot but there is still a lot to come, he is still a young fella. There’s enough time for that.

“In specific games he is outstanding; sometimes he is not as much involved as we want him to be. The full-backs in whatever system we play have an unbelievably important role, not only in defending but especially in attacking.

“It’s normal that he expects more from himself and I expect more because it’s obvious there is still a lot to come.”