Abel Resino's unpredictable side, who are fifth in the table, produced a thrilling performance to come back and beat leaders Barcelona 4-3 last weekend, blowing the title race wide open.
Barca's third league match in a row without a win allowed chasing Real to close the gap that stood at 12 points three weeks ago, down to four.
After doing their city rivals a favour, Atletico captain Maxi Rodriguez recognised the need to now offer a helping hand to their natural allies in Catalunya.
"(This time) I hope it will be the Barcelona fans thanking us and praising us on Saturday for a win over Real Madrid," he said.
The problem is Atletico usually wilt when they have the chance to really put one over on their neighbours.
They have to look back 10 years for the last time they won the derby, when Jimmy Floyd Hasselbaink scored twice in a 3-1 win at the Bernabeu in October 1999.
Saturday's game is unlikely to replicate last weekend's end-to-end clash at the Calderon. Real's 10-match winning streak has been built on more conservative foundations and they have only conceded twice in that run.
Atletico's shaky defence will be the deciding factor at the Bernabeu.
CUP FINAL
Barca received a lift when they qualified for the King's Cup final on Wednesday, but it was another unconvincing performance that took them past lowly Real Mallorca 3-1 on aggregate.
Holding a 2-0 first-leg advantage, they had to survive a red card and save a penalty before Lionel Messi scored to grab a 1-1 draw on the night. They have now gone five matches without a win in all competitions.
"We needed to get to the final after everything that has happened recently," Barca midfielder Yaya Toure said. "It's a huge lift and should allow us to get back to playing the way that made us unstoppable for three or four months."
On Saturday, Barca host the side they meet in May's final Athletic Bilbao. The Basque side swept to a 3-0 win over Sevilla on Wednesday to take their semi-final 4-2 on aggregate. Third-placed Sevilla are at home to Almeria on Sunday.
