Once a source of frustration amongst Liverpool fans, Alberto Moreno has been a star turned under Jurgen Klopp this season.

Three years on from joining the Reds from Sevilla for £12 million and the 25-year-old has finally become a regular in the starting XI.

It's consistency that Moreno has improved most in. Excellent one week and poor the next, the Spaniard has previously struggled to string together good performances at Liverpool.

But now he's found form and recently earned a call-up to the Spain national team, for whom he's only ever made three appearances.

Jurgen Klopp said of the call-up: "With Alberto it's really nice, he deserved it as well.

"I think it is quite difficult to get a call from the Spanish national team, they have not a lot of weaknesses and not a lot of problems at left-back.

"Obviously they watched him and so far he was really consistent this season. It's nice, really nice."

Moreno is in a good place at the moment, but that hasn't always been the case during his three years at Liverpool.

Back in 2015, when James Milner was brought to the club and Klopp later arrived as manager, Moreno eventually lost his place to the midfielder.

It was at the beginning of the 2016/17 season when Moreno realised he was no longer Liverpool's first-choice left-back, which he has now described as a "f***** up" moment.

Speaking to Marca, the Spain international gave a frank and x-rated interview detailing life under Klopp and how he reacted to being replaced by Milner.

"It's been strange. He (Milner) arrived and I played everything and at the beginning of the following season I disappeared," said Moreno.

"When I saw that a right-footed midfielder like Milner was the left-back, I thought something was happening. He (Klopp) didn't give me explanations.

"Already in summer I saw that the season was going to be f***** up and that's how it was. I cannot find a reason for what happened."

Can't fault Moreno for being honest - and you can hardly blame him for being frustrated.

Milner was excellent for Liverpool at left-back last season, but the fact remains he's a midfielder by trade, whereas Moreno is an out-and-out left-back.

But that's all in the past and now Moreno is Klopp's undisputed first choice down the left flank, even with Andrew Robertson now in the picture.