He lost his place in the team the following season to midfielder James Milner and started only two Premier League games, with his days at Anfield looking numbered when Liverpool signed Andrew Robertson from Hull City for 10 million pounds in July.
Moreno, however, returns to his old stadium, the Sanchez Pizjuan, on Tuesday having vindicated himself on Merseyside.
Moreno has played 16 of Liverpool's 18 games in the league and Champions League, completing each one, and this month was recalled to the Spain team for the first time in four years, boosting his hopes of going to next year's World Cup.
Moreno, who signed for Liverpool from Sevilla in 2014 for 12 million pounds, is now so indispensable for the English club that he missed the birth of his son to be with the team to prepare for Saturday's 3-0 win over Southampton.
Klopp praised Moreno's attitude for transforming his own fortunes after his peripheral role in the team last term.
"I never had something like this, I never had it to be honest. This season is not a surprise, the surprise is how he dealt with last season. There was not one bad word in the whole season," Klopp told the club's official website (www.liverpoolfc.com) on Monday.
"He was in my office, yes, he asked what he could do better, and we spoke about the things he had to do better. He's now a much better defender, that's how it is, he's a brilliant footballer."
MORE SETTLED
Moreno described his transformation in a recent interview with English newspaper The Guardian.
"Last year was useful for me: to think, to change things, to say to myself: 'Alberto, what can you do better?' And the first thing was: defend. I'm a defender. And I've changed that. I'm more focused, I think you can see that –- and thankfully I haven't made any mistakes," he said.
"Maybe in my first few years at Liverpool, I was always thinking: 'Attack, attack, attack.' Confidence is vital for a footballer but I'm more settled, focused: now I'm like: 'First, let's defend, keep a clean sheet and, then, let's go forward.'"
Liverpool have been criticised for their defensive weaknesses this year but head to Seville having conceded only one goal in their last four games.
They top Champions League Group E on eight points and a win at Sevilla will seal their place in the last 16 of Europe's elite competition for the first time since 2009. Alternatively, if Sevilla are the victors, the Spaniards will qualify for the next round with one game to spare.
(Editing by Clare Fallon)
