Former Barcelona attacker Rivaldo has insisted that the Catalan giants must "wake up as soon as possible" if they are to enjoy a successful campaign.

Barca have booked their spot in the last-16 stage of the Champions League but gave up first position in Group G courtesy of a 3-0 home defeat to Juventus on Tuesday night.

Ronald Koeman's side have also struggled in La Liga this season, picking up just 14 points from 10 matches to sit down in ninth, while they lost 2-1 at newly-promoted Cadiz last weekend.

Rivaldo has said that "things are getting uglier" at his former club as they continue to struggle for results.

"For now, I'm not seeing Barcelona producing enough football to fight for the Champions League title this season," Rivaldo told Betfair. "But things can change if they manage to knock out a strong opponent in the last 16 as it would boost their confidence.

"With stronger and more solid teams in the competition at the moment, Ronald Koeman's job will be to improve Barcelona by February to give them a real chance to fight in the last 16.

"If they keep under-performing then [failing to finish top-four] is a real possibility. The team isn't playing well, and things are getting uglier. It's crucial that they wake up as soon as possible and get back to producing good performances and results."

Barca will be looking to recover from back-to-back defeats when they host Levante on Sunday night.