He was outclassed by Windu in lightsaber combat and was scrambling. But he was not scared because Anakin had arrived. It is explained in the Revenge of the Sith novelization.
DARK SIDE FRIDAY - Did you know Palpatine feared Qui-Gon Jinn? Palpatine was immensely powerful and he could see the future which made him very confident about pretty much anyone who stood against him. So why Qui-Gon Jinn?
Palpatine Thought Windu Was More Powerful Than Yoda
Dooku feigned repentance, and wanted to meet with his former master. It was an attempt to assassinate Yoda, or else turn him to the dark side.
Palpatine's face was left disfigured after fighting Mace Windu, but despite Star Wars' medical technology, he never tried to heal his scars. In Star Wars: Revenge of the Sith, it was revealed that Emperor Palpatine's face wasn't just the product of old age but also scarring from fighting the Jedi.
Windu didn't beat Palpatine because he was stronger and more skilled in lightsaber combat - he beat him because of three major reasons: (1) his unique lightsaber style, (2) his Shatterpoint technique, and (3) he got lucky.
The showdown on Coruscant was a confrontation that took place in the Supreme Chancellor's Suite of the Galactic Senate in 19 BBY. It began after Jedi Knight Anakin Skywalker informed Master Mace Windu that Supreme Chancellor Palpatine had revealed his identity as a Sith Lord to him.
In short, he thought that the Jedi were becoming too subservient to the Republic and the Senate. That was on particular display in "Choices," when he and Master Windu were working as partners.
Giving in to his feelings, Anakin cuts off Mace Windu's hand, giving Palpatine the opportunity to kill him. Anakin regrets this almost instantly, but the thought of Padme was stronger than his remorse This is the moment Anakin officially became Darth Vader and led to serious issues in the Skywalker Saga.
Though the Clone Wars were all but over, the Jedi were in terrible danger. Anakin revealed to Mace that the Sith Lord sought by the Jedi since the fight with Darth Maul was none other than Palpatine himself.
Sidious himself felt that he and his peers had outgrown the use of lightsabers, and only continued carrying them to mock the Jedi. He ultimately viewed his own lightsabers as little more than an affectation, and rarely wielded them in combat.
Mace completely dismisses him as not just the Chosen One but also a Jedi. He seems particularly spiteful towards Ahsoka, especially when the last time the two interacted, he brushes off as a citizen. Then, he blantantly admits to not trust Anakin.
What Would Happen To The Galactic Republic? With Chancellor Palpatine's death, the de facto "Prime Minister" of the Republic, the Senate would be left without a leader and there would be considerable political confusion and chaos. There would be a need to elect a new chancellor to lead the democratic government.
Jedi Master Yoda is the most powerful of them all. This should come as no surprise, as he was the head of the Jedi Order in the prequels and was revered for his abilities during the original trilogy. Yoda's power is unmatched and was a real threat to Darth Vader and the Imperials.
If Qui-Gon had survived his fight against Darth Maul, he would have sensed Palpatine's evil, and Anakin wouldn't have become Darth Vader. Thus, while Qui-Gon was less powerful than Yoda, Palpatine feared him more.
First on the list of Palpatine's rivals is Darth Bane. He was not only unrivaled with a lightsaber in his day, but he was also a master at shrugging off the force powers of others, Sith and Jedi alike. As the sole surviving Sith of the Jedi-Sith War, his knowledge of the force should not be underestimated.
If Maul knew, he would have tole Obi Wan or another Jedi during the Clone Wars. Dooku knew Palpatine was Sidious as he told Obi-Wan about him controlling the senate and referred to him as the dark lord. There's no real way of actually knowing if he knew ab palpatine.
Jedi Masters Mace Windu, Kit Fisto, Saesee Tiin, and Agen Kolar confronted Chancellor Palpatine upon learning of his secret identity as a Sith Lord.
Mission to Mathas. Padawan Windu was trained in the ways of the Force by Jedi Master Cyslin Myr. Following his early trials as a youngling, Windu attained the status of Padawan by becoming Jedi Master Cyslin Myr's apprentice.
because his Padawan Ahsoka. never became a knight. She left the order when she was still a padawan. This is why Anakin was denied the rank of master.
As he turned to the Dark Side and became Darth Vader, Anakin came to hate Obi-Wan, but never stopped respecting him. In the end, it was Vader who would take Obi-Wan's life, but it was Obi-Wan who would set up the path for Anakin to be redeemed.
Anakin does not have even the slightest bit of remorse. By the end, he feels nothing but anger. Although he feels regret for killing Padme, he still helps the evil Emperor. The film ends with Anakins standing side by side with the man on whose behalf he has committed all his crimes.
Billaba became Windu's Padawan and trained under the Jedi Master in the ways of the Force. During her training, Windu allowed her to study Form VII variant known as Vaapad. She eventually became a Jedi Knight, renowned for her skills with a lightsaber and favored Form III when teaching other Jedi.
Bottom line, Dooku never considered himself a Sith. And he wasn't; he was a man looking to change the galaxy in a way the Jedi were unwilling to try. And that is why he joined the Sith and became Darth Sidious' apprentice, Darth Tyrannus. When Dooku became Sidious's apprentice, he was already an elderly man.
In one of the canon comics Sidious outright implied that Maul was pretty much head and shoulders above Dooku when adressing the potential. While Dooku was a useful pawn for him, Maul in the other hand seems to be actually his first choice as a heir before Anakin was really part of the picture at least.