Xavi Hernandez says Barcelona still need to strengthen their squad after opening the season with a disappointing goalless draw against Rayo Vallecano at Camp Nou on Saturday.

Barca handed debuts to four of their five summer signings against Rayo, with Robert Lewandowski, Raphinha and Andreas Christensen all starting. Franck Kessie came on in the second half.

All four of them were registered with LaLiga on Friday after the club sold 24.5% of Barca Studios to take the total raised from asset sales this summer to over €700 million.

Jules Kounde has not yet been registered and won't be until Barca create more salary space, but the Blaugrana are pursuing further signings, with Marcos Alonso, Bernardo Silva and possibly another right-back all wanted.

"I've already said we have to keep strengthening and we have time until Aug. 31 [when the transfer window closes]," Xavi said in his post game news conference.

"But I don't want to use that as an excuse [for the Rayo result]. I understand the disappointment, expectations are really high. We will have to analyse the game, improve and keep believing in the model of play.

"Rayo defended well. It was harder for us to create [chances] than usual. It's a shame because we wanted to show the fans that we're on a good path. It's disappointing, but we ask for patience."