The Spaniard has called on the Frenchman to deliver a match-winning performance as his side bid to reach the Champions League final
The European champions enter the second leg of their Champions League semi-final tie a goal behind thanks to Karim Benzema's strike in the first encounter last week.
Ribery, who has gone through a difficult run of form of late, scored in the weekend's 5-2 victory over Werder Bremen and the Spaniard wants the French winger to deliver a match-winning performance against the Spaniards.
"Franck Ribéry is very important and necessary for us," he said at a press conference.
"He has been at Bayern longer than me. I am happy of course if he plays well, with energy and motivation. He sometimes needs an angriness and I am sure he will play very well tomorrow.
"He has this fighting spirit. He always wants to fight, that’s why the people love him. He is one of the most fantastic players in the history of Bayern."
Guardiola admitted that his side were disappointed not to come away from the Santiago Bernabeu with an away goal to their name.
"We wanted to score an away goal. Now, even more so, we have to attack and we have no other chance. We have to take care of their counterattacks.
"Being in the semis, you are closer to the final. In Madrid they saw that they are very close to the final. We can't make it by ourselves tomorrow.
"We need the fans who have been outstanding before. I am sure our fans will be there for us tomorrow. We can make it to the final. The team want it, I want it, the fans want it. Together we can achieve this.
"Real are very fast, they run a lot. If you lose the ball, you need to close the spaces and a good set up in defence. I have to prepare for different scenarios.
"Most of the time they dominate games, they can play more offensively or more defensively – we have to be prepared for everything.
"They will try to defend the advantage they have for 90 minutes. With which tactics, we will see. It does not matter who Real pick. I can't judged this. [Carlo] Ancelotti will decide.
"Their 11 players will attack and defend together. We have to concentrate on the whole team."