Frank de Boer says holders Real Madrid are the team to beat in the Champions League, but thinks the presence of Lionel Messi means it would be foolish to write off his former club Barcelona.
Former Inter boss De Boer, who played at Camp Nou between 1999 and 2003, feels Madrid coach Zinedine Zidane deserves credit for the team spirit he has built.
But the Dutchman says Barca, who face Paris Saint-Germain in the last 16, are among their strongest challengers for European glory, particularly now midfield duo Sergio Busquets and Andres Iniesta have returned from injury.
Despite Barca trailing Madrid by a point having played two matches more in LaLiga ahead of the Champions League's return, De Boer does not think Luis Enrique should be under pressure.
"Yeah [Madrid are team to beat] - they have proved they are very solid," De Boer, speaking as a William Hill ambassador, said at the London Affiliate Conference
"They are difficult to beat and they have the quality with Cristiano Ronaldo, who always gets his goals.
"Zidane has made a team that really wants to fight for each other and that is paying off right now.
"[But Barcelona are] always one of the favourites. When you have Messi in the team, you are always are."
On whether Luis Enrique should be facing pressure, De Boer added: "No, not at all. They have to lose some more games for that. I think he is still sitting firmly there.
"People underestimate what an impact someone like Busquets has in the team, he is a very experienced player and at the centre of the game. The same for Iniesta, of course, with his experience.
"They were injured a couple of weeks so they were missing them really hard.
"They are fit again for the Champions League and LaLiga, so hopefully for Barcelona will get their level up again when they return.
"Barcelona when they are 100 per cent with Busquets and Iniesta back then they have a very big chance to go through to the next round.
"But last year I was really impressed with how PSG played, so maybe it is going to be a tight game."