It will be "immensely difficult" for Real Madrid to improve their squad but they still plan to make more signings in the close season, new coach Rafa Benitez said.
The Spaniard was brought in to replace sacked Italian Carlo Ancelotti after the world's richest club by income failed to win any of the three major trophies in 2014-15.
Before Benitez's arrival Real bought Brazil full back Danilo from Porto for 31.5 million euros ($36 million) while Brazilian defensive midfielder Casemiro is to return from a loan spell with the Portuguese side.
Manchester United and Spain goalkeeper David De Gea is poised to join the Madrid club, according to media reports, and Real are also believed to be chasing France midfielders Paul Pogba and Marco Verratti.
"Of course," Benitez replied when asked in an interview published on Real's website (www.realmadrid.com) if there would be new faces in the close season.
Danilo and Casemiro, for example, are players who are going to be important and the club is working every day to try to raise the level of this team with the odd signing that can help us to tackle the challenges ahead of us," added the 55-year-old.
"But let me say that improving the current Real Madrid squad is immensely difficult.
"This team has won everything and has shown the level it has. The fans can rest assured that this squad will possess the level of competitiveness that is demanded of this club."
Benitez also reacted to reports that forwards Cristiano Ronaldo and Gareth Bale were not happy with the positions they were typically played in by Ancelotti.
Ronaldo usually starts on the left, although he has licence to roam, with Bale on the right and France striker Karim Benzema through the middle.
Portugal forward Ronaldo, Real's top scorer and the World Player of the Year, is keen to play in a more central role while Bale wants to play just behind a front three, the reports said.
One of Benitez's trickiest tasks will be to maintain harmony among the egos in the dressing room while also meeting the demands of hands-on club president Florentino Perez.
"Contrary to what is being said ... none of them are 'demanding' to play here or there, among other reasons because we haven't yet decided the most appropriate system with which to try to get the most out of each player," Benitez said.