Virgil Van Dijk excited by Liverpool's new-look attack after United thrashing
January-signing Cody Gakpo and Darwin Nunez, who arrived last June, both scored twice at Anfield on Sunday while Mohamed Salah also grabbed two goals.
With Roberto Firmino, the other goalscorer, set to leave at the end of the season, only Salah remains from the famed frontline that also included Sadio Mane, now at Bayern Munich.
Nunez has scored 14 goals this season while Gakpo has netted four goals since arriving from PSV Eindhoven.
Defender Van Dijk hailed Liverpool's "world-class" strikes at Anfield, describing Gakpo's first goal as "outstanding".
"Obviously it's been a difficult time to come in any club, I think, in the winter for any player but he's settling in very well," he said. "It's a very difficult position to play.
"Obviously he learns from one of the best, I think, each and every day with Bobby Firmino. He has to keep going, keep the confidence, keep the belief and stick together.
"I think he will be fine for this club and I mentioned it already before but he's a fantastic player. Darwin is causing chaos all the time with his speed, his passion and also with the quality."
Egypt international Salah scored his 128th and 129th Premier League goals for Liverpool to become the club's record scorer in the competition.
Van Dijk said while thumping their arch-rivals was enjoyable, nobody would be dwelling on the result as Liverpool chase a top-four finish after an inconsistent season.
Jurgen Klopp's team are currently fifth in the Premier League, three points behind Tottenham with a game in hand.
"We should not take these results for granted but there are many more games to play in order to get what we want - in this case that's Champions League football and that's what we focus on," said Van Dijk, the Netherlands captain.
"We shouldn't just brush it off like it's any other day. We won 7-0 in a difficult season that we've had. You should be able to stand still and enjoy that a little bit.
"But the focus will turn and it's another week towards Bournemouth. I think our focus has always been one game at a time and that doesn't change."