Spanish and European champions Madrid have struggled in the first half of 2017-18 and sit fourth in the table, 11 points behind leaders Barca and five back from second-placed Atletico Madrid.
Earning all three points at the Santiago Bernabeu would be a huge boost to Barca's hopes of reclaiming the domestic crown.
But Valverde, speaking after his team's 4-0 win at home to Deportivo La Coruna on Sunday, talked down the significance of the eagerly anticipated clash.
"I don't think a Clasico victory will give us the title," he told a news conference.
"Atletico are only six points behind.
"What we know is that this is a long competition, nobody will decide anything at this point.
"We're heading into the game happy.
"We have a week of preparation left and are confident.
"It's a tough game against a huge rival, but we're eager to face them."
Valverde withdrew Andres Iniesta early in the second half to preserve the veteran midfielder for the trip to the capital next weekend.
And the former Athletic Bilbao coach was delighted with the contribution of a player whose inch-perfect pass enabled Lionel Messi to set up Luis Suarez for the opening goal of the game at Camp Nou.
"What can I say? I'm very lucky to be able to count on him in my team," Valverde said.
"Today he started in a different position because of Deportivo's qualities.
"Andres played extremely well in that role."