I feel that Real Madrid will win this derby because their performance is indeed better than Atletico Madrid. Their front line is indeed not at its best yet, but from what I see they are on fire and are quite productive so far. Meanwhile, Atletico Madrid have looked shaky in their last 2 matches. They could only draw against Rayo Vallecano and although they managed to get a win against Celta Vigo afterward, but they didn't really dominate the game. Atletico Madrid were quite lucky that Celta Vigo did not have a good finishing touch.
That's quite some confidence given that is only two points ahead, they are playing away from home and Atletico Madrid has the best defense in the league. Additionally, Mbappe is injured. That game is going to be very hard for Real Madrid as Atletico is kind of the underdog and has less to lose in this game. The winner of the matchday could clearly be Barcelona if either Atletico wins or they end the game with a draw.
But Osasuna not a walkover for Barcelona. 7th rank and although I doubt that Barcelona lose points here, it is of course always possible. But a win would be huge. It would be nine and seven points respectively against Atletico and Real and both know that a loss would be very painful then.