The Catalan giants host their fierce rivals on March 22 to cap a crucial month in their season as they look to stay in contention for three trophies.
Saturday's victory over Granada – combined with Real's draw with Villarreal – moved Barca within two points of the leaders.
However, Busquets says they cannot let the Clasico take their attention away from the four games prior to it, otherwise their season could unravel.
"There's still a couple of games before then, but let's hope it is decisive for us," said the midfielder. "A lot depends on what happens in games before it.
"We know we've got to win every game. Being two points behind doesn't change anything about way we think, we always try to win all our games.
"Last week they [Real] were four, now it is just two, it means we don't have to depend on other results going our way, but it won't change way we play football."
Ahead of the Madrid clash, Barca travel to Villarreal in the Copa del Rey semi-final second leg on Wednesday, before facing Rayo Vallecano and Eibar in the league, and Manchester City in the UEFA Champions League.
‘After Manchester City’s recent form, maybe they’re the underdogs against Manchester United!’ Former Red Devils defender on this weekend’s derby
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
