Xavi Hernandez says Barcelona taught Real Madrid "a footballing lesson" in Saturday's Clasico.
Madrid suffered a 4-0 defeat at the Bernabeu, leading to questions over the futures of both coach Rafa Benitez and president Florentino Perez as the capital club fell six points behind their arch-rivals.
Xavi, who left Barca for Qatari club Al-Sadd in the summer, told EFE that Luis Enrique's men could easily have matched the five-goal victory they enjoyed over Jose Mourinho's Madrid side in 2010.
"Although they didn't get the manita [the little hand, meaning five goals] it could have been much more than five for the chances they had," he said.
"Madrid, too, had two or three, but Barcelona had more than 20 clear chances and it could have been a bigger goal haul."
He added: "It was an historic game -- 0-4 at the Bernabeu -- and moreover with the way they played football. I think Barcelona gave a footballing lesson yesterday, an incredible one in my opinion. I enjoyed it a lot in the hotel and I congratulated them."
Xavi, who was in Doha for the game, said he had enjoyed the experience of his first Clasico since leaving the Camp Nou.
"I had a great time, because Barcelona were far superior in every aspect -- in attack, defence, pressure, intensity," he said. "It was a truly incredible game from Barcelona."
His favourite part of the game was seeing his former midfield partner Andres Iniesta fire home the third goal in the 53rd minute.
"All the goals were great, but Andres' was spectacular," he said. "I think the whole team was a 10 out of 10."