Barcelona - Barcelona have to strengthen a squad depleted by the departure of Neymar, influential midfielder Sergio Busquets admitted after the Catalans suffered a 3-1 home defeat to rivals Real Madrid in the first leg of the Spanish Super Cup on Sunday.
Neymar joined Paris Saint-Germain earlier this month for a world record €222 million euro fee, but Barca's attempts to replace the Brazilian have so far fallen short.
"It is a question of renewal and always trying to get better. We have to (sign) whatever happens." Busquets told Spanish TV station Telecinco.
Cristiano Ronaldo was at the heart of the action at the Camp Nou despite only appearing as a second-half substitute, scoring a sensational goal and being controversially sent off.
Lionel Messi's penalty had cancelled out Gerard Pique's own goal early in the second-half to give Madrid the lead.
Ronaldo then curled into the top corner 10 minutes from time, but was booked for taking his shirt off in celebration.
And that proved costly two minutes later when he saw a second yellow card after being adjudged to have dived when trying to win a penalty.
Despite their numerical disadvantage, Madrid extended their lead late on when Marco Asensio fired home in style from the edge of the box.
"It will be difficult to turn it around," added Busquets ahead of the second leg at Madrid's Santiago Bernabeu on Wednesday.
"They have made it difficult, almost impossible."
Barca have been heavily linked with moves for Liverpool's Philippe Coutinho and Ousmane Dembele of Borussia Dortmund and coach Ernesto Valverde.
And after the disappointment of defeat in his first game in charge, Barca boss Ernesto Valverde said his aim was to have the best team possible by the time the transfer window closes on August 31.
"We are Barca and we want the best possible team," he said.
"Until August 31, like every other team, the market is open to us."
By contrast, Ronaldo's 10th red card of his career was the only negative of the night for Madrid coach Zinedine Zidane as he closes in on a seventh trophy in less than two years in charge.
"What annoys me is the sending off for Cristiano," said the Frenchman.
"Even if it is not a penalty, the card is harsh."
Yet, Ronaldo could be slapped with more than a one-game suspension as he lightly pushed referee Ricardo de Burgos Bengoetxea in his frustration at being dismissed.