Jurgen Klopp dismissed the questions over Liverpool's strength in depth after revealing Roberto Firmino is closing in on a return.
Firmino has been absent since limping out of the 1-1 draw with Chelsea on August 28 early with a hamstring injury.
The Brazil international is now back in full training ahead of a busy end to the month for the Reds that sees them play Brentford and Porto before a visit from Manchester City on October 3.
Klopp said: "Bobby trained on Monday for the first time for the team, so he is not too far away from playing again.
"Now we have obviously two midfielders out (Thiago Alcantara and Harvey Elliott), so we try to make sure that number doesn't get bigger.
"The start of the season, obviously so far it has been good for the whole squad, but it is only the start. There is a lot more to come."
Two goals from Takumi Minamino either side of Divock Origi's header saw the Reds score three times for the fourth successive game.
Some have questioned the quality of Liverpool's reserves after the sale of Xherdan Shaqiri in the summer, but Klopp is in no doubt about his options after they cruised into the fourth round.
He added: "It's just a logical thing. Taki (Minamino) is in a really good moment but didn't play too much, came back from the national team and had to get fit, sometimes it is easier, but he is a top character.
"I enjoyed his game tonight. He was causing them problems tonight, so that will help him and help us.
"I was never in doubt about that [strength in depth], I have said it before.
"I am not sure it was frustrating for Taki, a footballer wants to play, that's clear.
"He was with the [Japanese] national team, got injured there, came back and was not fit immediately, but he got fit again since he came back and it is not that he hasn't played for 16 weeks or whatever.
"It was just the time now after his injury and players need time to get back on track.
"But Taki is in a really good moment, he trained really well and the first goal was really good awareness, quick of mind, and he finished it off.
"The second one I didn't really see 100 per cent, but he got into the box and scored in a small space.
"He was really, really good. He got injured, then came back, so nobody has to worry, Taki will be fine."