Jurgen Klopp lavished praise on Aston Villa's young players after they made Liverpool battle for their place in the FA Cup fourth round on Saturday (AEDT).
As a result of a training ground COVID-19 outbreak on Friday, the hosts were forced to send Under-23s boss Mark Delaney and a team comprised of youngsters to face the Premier League champions at Villa Park.
They more than held their own for large parts, and even got to the half-time break level thanks to a well-taken Louie Barry goal.
Liverpool took the game away from Villa in the second period, ultimately running out comfortable 4-1 winners, but Klopp was impressed with what he saw from the opposition.
The German also took pleasure in the fact his far more experienced side eventually solved the 'football problems' in front of them.
He said: "The boys did really well, the kids of Aston Villa did really well, were organised and all that stuff.
"It was clear. We scored an early goal, a nice one, and then we didn't play quick enough anymore, didn't move fast enough, didn't play the right spaces.
"These are football problems and we solved the football problems with football in the second half. So, I'm really fine with it.
"It was a tricky one. I've never before had this kind of challenge in my life, that you have no idea who you're playing against – absolutely no idea; that you prepare a meeting and then you can throw all the preparation, all the videos in the bin and then you have to start new.
"That's football and academy players are good players. Last year we played here with our kids and they gave Aston Villa a proper game as well. That's just how it is.
"These young kids can all play football and if you don't play well against them you have problems. Second half, we played exactly like we should have played from the beginning and that's why we won really, the right way."
Klopp withdrew captain Jordan Henderson at half-time in Birmingham but went on to reveal that the change was not down to a new fitness issue.
Asked about a possible injury blow, he replied: "No, no, Hendo and Thiago was clear before the game that we do it like this: 45, 45. Absolutely no problem."
The German also explained that he had no concerns about his squad being exposed to coronavirus despite the late change to Villa's proposed line-up.
He continued: "No, no reservations. We trust the authorities, we had our test results come back yesterday as well, everybody was negative. Then the FA did what they thought is right with the U-23s, they got tested, we got their results this morning I think at 10 o'clock.
"We were on the car park at the airport. So, then everything is fine."