Barcelona's faint hopes of catching LaLiga leaders Real Madrid suffered a huge blow as they slipped to a shock 1-0 home defeat by relegation-threatened Cadiz on Monday.

Real's last-gasp victory at Sevilla on Sunday extended their advantage over Barca in second to 15 points, but Xavi Hernandez's in-form side were expected to close the gap by beating Cadiz at the Camp Nou.

The hosts never really got going, however, in front of a disgruntled crowd and Cadiz had the better first-half openings with Lucas Perez missing a glorious opportunity to break the deadlock.

Cadiz kept coming after the interval and Perez scored in the 48th minute before the visitors wasted further big chances to extend their advantage - Alex Fernandez slotting wide when it looked easier to score.

Barca piled on the pressure but lacked that killer pass as they slipped to a first defeat in 16 LaLiga matches stretching back to December. They remained on 60 points from 31 games, 15 behind Real who have one hand on the trophy.

“We had the chances, more than enough to take the three points, but we have to rise from this and think about the next games,” Xavi said.

“We have to change our form as soon as possible. We have got back into the Champions League places but we have to keep going.”

“It's a very bad week for us and we need to change the dynamic as soon as possible.”

Aside from their shock Europa League exit at home to Eintracht Frankfurt last week, Barca have enjoyed a revival under Xavi in recent months to climb back into the title race. (Reuters)

•PHOTO: Soccer Football - LaLiga - FC Barcelona v Cadiz - Camp Nou, Barcelona, Spain - April 18, 2022Cadiz coach Alvaro Cervera remonstrates with referee Santiago Latre REUTERS/Albert Gea