The Germany international eventually regained his feet and was helped from the pitch, rather than having to be carried off on a stretcher, but immediately after the game it was too early to know the exact problem or its extent.

Asked about Can, Klopp said: "I have no idea. He had a little pain in his ankle without any touch - I couldn't see any contact. It was a long leg, then a little bit floppy and then he had pain.

"But it is not that serious. It's not that big [of a] pain any more, but it's the ankle he had problems with at the end of last season, so he's a little bit worried.

"Hopefully it's nothing too serious."

Can departed with Liverpool having all but won the tie, leading 3-0 following two quick first-half goals from Divock Origi and Roberto Firmino and a second-half own goal by Reds fan Tom Naylor.

Substitute Daniel Sturridge netted a late double as Klopp's side blew away the cobwebs of Saturday's surprise 2-0 defeat to Burnley.

Against the Clarets Liverpool were laboured in their build-up, particularly in the first half, and careless and wasteful in possession and Klopp demanded more cutting edge from his players.

He felt it was a step in the right direction at the Pirelli Stadium, saying: "There were still a few situations where we were missing a bit of sharpness but the main problem was, it was unbelievable, our build up and style of play at Burnley - one more pass but 15 times we are completely free in the box.

"So we needed to use this game and that's what we did and it was better."

Origi marked his first start of the season with a goal while Sturridge will also hope to have given Klopp something to think about when making his team selection for the Premier League trip to Tottenham at the weekend.

"Of course in the end we have to make decisions but what I have to do is pick the right players to make the right solutions," said Klopp.

"The job the players have to do is be in the best shape. It is clear what both sides have to do but they are difficult decisions."

Burton boss Nigel Clough, a former Liverpool striker, knew the size of the task facing his side side was enormous but his focus was always the Championship clash at home to neighbours Derby on Friday night.

"It's difficult for our lads to compete with that sort of quality," said Clough.

"Derby isn't more important - it's the only important one. With tonight, we managed to get through in the last round and got a great draw.

"With this being 72 hours before the Derby game, our focus was always with that one.

"It was (invaluable experience). When you think we finished with a couple of teenagers and a 20 or 21-year-old, you could train with them for a couple of seasons and not gain the experience they've got tonight."