Joel Matip in action during Liverpool's EFL Cup win at Burton

Jurgen Klopp says he never doubted Joel Matip had the quality to be a success at Liverpool.

The Cameroon defender was a low-profile summer arrival on a free transfer after leaving Bundesliga side Schalke, and a foot injury kept him out at the start of the season.

But Klopp has picked Matip to partner Dejan Lovren for three successive games in central defence, a draw at Tottenham and wins over the Premier League's two most recent champions, Leicester and Chelsea.

Speaking to the press ahead of this week's EFL Cup tie with Derby, Klopp said: "If you lived and worked in Germany you would have known much more about him. It was pretty clear it would make sense to sign him.

"Tall players like him need physical fitness. He needed to create some physical strength, but there was never a doubt about his quality."

Matip was brought in with fellow defender Ragnar Klavan this summer as Mamadou Sakho was advised to leave Liverpool on loan.

Chelsea 1-2 Liverpool Chelsea 1-2 Liverpool

The France centre-half stayed put but is yet to feature this season, and Klopp said on Monday: "Of course he is closer, he is still working. But match fit is a big difference. That's all. It's not about only making a few sessions.

"It's not about how the player feels. It's about how I feel and how close the player is. That needs time. It's a long, long time that he didn't play, for sure.

"All the other players had not that long a break. Then it makes more sense that you really use the time and that's what we are working on.".

One player who could return at the iPro Stadium is Roberto Firmino, who missed Friday night's win at Chelsea with a minor groin problem.

The Brazilian trained with his team-mates on Monday and is in contention as Klopp prepares to field a strong XI.

"You can be sure we will find a strong line-up again for this game," the German said. "It is not about resting 100 per cent fit players, it is a normal rhythm and a rhythm we want to have next year again every three or four days."

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