Casemiro suggested Real Madrid winning the Champions League would be a greater achievement than Barcelona's domestic double.
The La Liga champions extended their season-long unbeaten run in the top flight with a 2-2 draw in Sunday's Clasico at Camp Nou.
Sergi Roberto's dismissal at the end of the first half for appearing to strike Marcelo in the face looked set to make the Catalan giants' task tougher, but Lionel Messi restored the lead cancelled out by Cristiano Ronaldo - who was replaced at half-time due to injury - before Gareth Bale completed the scoring in the 72nd minute.
Madrid have little to play for until contesting the Champions League final against Liverpool, with Casemiro claiming a third consecutive European title would eclipse Barca's exploits.
"It does not matter if Barca are already the champions," Casemiro said to Movistar.
"I prefer the Champions League final, congratulations to them because maybe they have played better in La Liga.
"They had one less [player], but the quality of their players was seen at 2-1. Without Cristiano we lost a bit in the second half, but hey, a fair result."
Madrid felt Messi's goal should have been disallowed for a foul by Luis Suarez – who scored the opening goal – on Raphael Varane in the build-up, while Marcelo appeared to be tripped in the box by Jordi Alba late in the game.
"The referee could have given a penalty for Marcelo," Casemiro added. "But we cannot talk about him, the referee wants to do his best. It was a draw, a great match for both sides."
Suarez, meanwhile, admitted he did not expect play to continue after his challenge on Varane.
"Varane controlled it and I just put my foot in," Suarez said. "But hey, that's the decision of the referee, sometimes they get it right and sometimes not, I was a little surprised that he let it go on.
"We went ahead twice on the scoreboard. Sergi's red card hurt us, but the team did spectacular physical work, defended well. The draw was not bad either."
