With all of their Premier League rivals strengthening, Klopp's side have endured a somewhat quieter close-season, adding Mohamed Salah, Dominic Solanke and Andrew Robertson.
That has come as city rivals Everton have made numerous signings and United, who also finished outside the top four last season, have added Romelu Lukaku.
But Klopp is unconcerned by what his team's rivals are up to, even if Mourinho wants to talk about Liverpool and the tougher workload they face this season with European football.
"I'm not interested in what Jose Mourinho says. Why should I talk about Manchester United? Jose is talking about us, yes," Klopp told UK newspapers.
"We had a season of what Man United had the year before. I don't know if anybody asked us how it felt."
But Klopp is calm about his side's transfer business, saying his focus was on what his team could produce.
"After a season there is a summer break and everybody starts — and I've said this before — feeling that the transfer window is more interesting than the league," he said.
"People think: 'Oh we are winning already' — but unfortunately after the transfer window you have to carry on playing. That's what I am most interested in.
"It doesn't mean we don't want to bring players in. We've always brought players in. Wonderful players like [Georginio] Wijnaldum.
"Maybe people know why I've said we are not doing too badly. Joel Matip. Again, Sadio [Mane]. A lot of good players already.
"But, it was not like — I don't know — [Zlatan] Ibrahimovic, Lukaku and others. Does that mean we can't do it? I have no idea. We will see."
Liverpool's begin their Premier League season with a trip to Watford on August 12.