Bruno Guimarães has admitted Newcastle need to keep their best players if they are to establish themselves as a Champions League force.
The Magpies lost star striker Alexander Isak to Liverpool after a protracted summer saga, and although they netted £125 million ($171m), which they have since invested in record signing Nick Woltemade and Yoane Wissa, the gap the Sweden international left will take some plugging.
Skipper Guimarães, who lifted the Carabao Cup last season, is desperate for more success and he knows that will only be achieved if head coach Eddie Howe can build his squad over a sustained period.
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Asked what the club could do to ensure that happened, the Brazil midfielder said: "It's a good question, and I don't know what the club can do.
"You have the financial fair play and I don't know if this effects things or not -- I'm not under the table to see the circumstance to see what was going on. Football is business.
"As a player, we don't want to lose our best players if you want to be successful. We have to improve our squad, and I think we did this very well in this summer. We look forward to going again."
Champions League football for the second time in three seasons allows Howe and his players to go again, but they could not have been handed a much tougher first-night assignment with Barcelona providing the opposition at St. James' Park.
Still, Howe said he believes Newcastle are better equipped than they were in their last Champions League campaign, when they failed to make it out of the group stage.
"There were a lot of unknowns last time," he said. "The focus was always on trying to get through the group stage, but there was a feeling we were experiencing something new.
"We enjoyed it, but ultimately we failed, so this time the resolve is stronger to try and progress, not just to enjoy the experience, but to try to make it a meaningful one.
"I think the squad is arguably stronger than it was two years ago. Certainly the squad is different and I will back the quality we have. They are all tough games, tough-looking fixtures and the early games are really important for us to set the foundations."
And Guimarães is relishing the opportunity to line up against the club which helped him to fall in love with football.
He said: "I'm very excited. I've never faced Barcelona before. It's one of the teams that I watched when I was young.
"The player that made me fall in love with football was Ronaldinho, so I always watched Barcelona play, and after [Andres] Iniesta, Xavi, [Lionel] Messi -- and it's nice to see another Brazilian sign there again, Raphinha, so we're very excited."
Iniesta and Xavi were star midfielders in the Barça team which was so successful in LaLiga and Europe during their illustrious careers, and Guimarães knows he, compatriot Joelinton and Italy star Sandro Tonali still have something to prove on the European stage.
Asked how good Tonali is, he replied: "Very good, very, very good. I enjoy playing alongside him. I think we complement each other -- I think he enjoys playing alongside me as well. We have a very good connection with Joe as well.
"I think we have one of the best midfields in the Premier League, to be honest, and now we have to prove it in the Champions League as well."
Information from PA was used in this report.