Klopp also revealed he did not change the team he meant to pick for the tie at Villa Park, even though he knew his side were facing a team of junior players.
Villa was plunged into the desperate situation following a coronavirus outbreak in the first-team squad that led to the closure of the club's training ground this week.
Liverpool are back in cup action on Friday evening.
This early warning was evidence that Jürgen Klopp left little on the bench little despite it not being a Premier League match.
Gini Wijnaldum, Mo Salah and Mane all found the net in the devastating spell to earn Liverpool a place in round four.
"The kids did really well", Klopp said. We had football problems.
"I would have loved if Jurgen Klopp had gone, "you know what, just because we're Liverpool and we respect what's happened at Villa Park, we'll go with Under-23s too". It was rusty but better in the second half". "We have a lot players with no rhythm".
Mark Delaney, Villa's under-23 coach, is scheduled to take charge in the absence of Smith and his backroom staff. "That was a monumental effort considering what the players have had to go through".
"We have a lot of players with no rhythm", he toldBT Sport after the win against Villa. They were also knocked out of the Papa John's Trophy at the group stage having lost all three of their games and ending on a goal difference of -12. The Premier League can ill afford for the season to be disrupted, and risk facing further rebates to broadcast partners.
"In the first half I thought they defended very well but in the second half you could see they were exhausted and starting to get worn out and that's where we started to dominate the game".
On Tuesday, a record high of 40 positive tests were detected among Premier League players and staff in the week between Dec 28 and Jan 3.
Newcastle boss Steve Bruce and Leeds manager Marcelo Bielsa claim there is a moral argument to suspend all matches after the latest national lockdown ordered by the government.
The news of the outbreak at Villa also raises questions about how and whether their upcoming Premier League matches can go ahead.
This gives them just 4 days to prepare for the top of the table clash against the Reds.
The opening goal came after four minutes, and Villa must then have feared a thrashing.
Villa's 19-year-old goalkeeper Akos Onodi denied Fabinho and Mane before Barry stunned the visitors.