Barcelona look set to runaway with the La Liga title after Real suffered a 1-0 defeat on home soil to Villarreal on Saturday.
With 16 points between the Blaugrana and Los Blancos in the standings, Kroos believes fourth-placed Real must switch their focus now on simply qualifying for the Champions League for next season.
"We have to focus on qualifying for the Champions League next season," the German international told beIN Sports. "We have to think about our current position. I think this should be our goal for the remainder of the season.
"Sixteen points is very far away and now isn't the time to think about anything other than the next game. We have to start gaining points once more. This will allow Real to get closer to their goal of finishing inside the top four."