The centre-back believes the Catalans are in fine shape for the match against their arch-rivals, while Alexis Sanchez has stressed they desperately want to beat Madrid
There were doubts over the Catalans' form after poor showings against Sociedad and Valladolid, but Bartra feels they showed at the weekend that there's no reason for concern.
"We're in fine form ahead of the game against Madrid," the defender told the club's official website.
"I’m very happy with how the team played. We are where we have to be. In these matches you have show your rival that they don’t have a chance.
"We were aware that a win against Osasuna would give us tranquillity ahead of the Clasico, but we must not lose focus."
The centre-back then went on to praise Lionel Messi, who scored a hat-trick to become Barca's all-time top goalscorer.
"Leo is spectacular. I have no words, every day he breaks more records."
Alexis Sanchez, meanwhile, was equally pleased with Barcelona's performance against Osasuna and has stressed they have set their sights on the full three points versus Madrid.
"We’re in the fight for La Liga. We will try to defeat Madrid.
"Both teams are worldwide football powerhouses, but the objective for Barca is to go there and win."