Eddie Howe admitted on Friday that Newcastle are still dealing with the fallout from Alexander Isak's protracted move to Liverpool in the summer transfer window.
The Sweden forward effectively went on strike in an attempt to join the Premier League champions, eventually securing a British-record £125 million ($172 million) transfer on deadline day.
Newcastle spent the money on club-record £69 million signing Nick Woltemade and Yoane Wissa, who cost £55 million.
But Magpies manager Howe, whose team face Liverpool at Anfield on Saturday, said that integrating the new players was "an ever-challenging thing".
"You lose a player like Alex... and let's put this right, Liverpool paid the money they did because he's an outstanding footballer, an unbelievable talent," he said.
"We were privileged to have him for the years that we had him. We loved working with him.
"He was an outstanding player. When you take that player away from your team, it's going to change the dynamics, that's for sure."
Howe said that the challenge was to find players who could come close to replicating Isak's prolific Newcastle form.
Germany international Woltemade has nine goals in all competitions for the Magpies this season, while Wissa has netted three times in an injury-hit campaign.
"We're still in that moment and we've been trying to do that all season," Howe said. "I think the guys who have come in have done a very good job.
"But we're still finding ways to get the best out of the new players that we've signed without training, with very minimal time to do any work with them."
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ISAK RECOVERY
Isak is recovering from an operation on an ankle injury that included a fibula fracture, which has wrecked his first season on Merseyside.
Liverpool manager Arne Slot said on Friday that a return for the forward was still a long way off.
"He's not even on the pitch yet," said the Dutchman. "I think it's called a walker, he's just out of his walker, so that tells you that he's not on the pitch."
Newcastle trail Liverpool by three points, and head for Anfield boosted by Wednesday's 1-1 Champions League draw at holders Paris Saint-Germain.
They will face Azerbaijani team Qarabag in next month's play-offs, with a place in the last 16 at stake.
Howe added that Brazilian midfielder Joelinton was likely facing "weeks, not months" out of action following treatment on his groin issue.