First Duel on Coruscant

The First Duel on Coruscant was when Anakin had discovered that Chancellor Palpatine was Darth Sidious, the Dark Lord of the Sith. He had informed Qui-Gon Jinn and Count Dooku minutes after Obi-Wan led a clone army to defeat droid armies on Utapau.

The Arrest Team
Qui-Gon had always thought that Palpatine was a Sith Lord and was put in charge of the arrest. He left Mace Windu and Kit Fisto in charge of the Jedi Temple. Qui-Gon and his master Dooku chose Saesee Tiin and Agen Kolar to assist them.

Anakin's Decision
Anakin needed Palpatine to help him save Padme, who might die from child birth. He rushed to the Chancellor's Office with R2-D2 in his Jedi Interceptor.

The Duel
Qui-Gon arrived along with Dooku, Tiin, and Kolar. They stormed into the Chancellor's private quarters and found Palpatine greeting them all. Qui-Gon, Dooku, Tiin, and Kolar activated their green and blue blades. Palpatine was furious and pulled out his lightsaber. The duel had begun after Palpatine leaped over to the Jedi. He stabbed Agen Kolar in the skull. Palpatine had secretly turned on a recording device, which he then destroyed after screaming for help. His help would have likely been from his Rodian aide Dar Wac, who left seconds before the duel. Anakin arrived and witnessed the duel, however he only saw one red blade, two green blades, and a blue blade. When one of the green blades disappeared, Anakin rushed into the Chancellor's private quarters and saw the dead bodies of Saesee Tiin, who was the recent death, and Agen Kolar. He then rushed to the Chancellor's Office to find that Qui-Gon and Dooku disarmed Palpatine. Qui-Gon cornered the chancellor while Dooku guarded Anakin from interferring. Palpatine then tried to attack Qui-Gon with force lightning, but Qui-Gon deflected it back at Palpatine, disfiguring him. Anakin tried to warn his friends not to kill Palpatine, but Dooku and Qui-Gon didn't listen. Just as Qui-Gon was about to deliver the killing blow to the chancellor, but Anakin turned on his blue blade and cut off Qui-Gon's saber hand. He then prevented Dooku from attacking by impaling him. Palpatine then attacked Qui-Gon with a second wave of lightning and threw him off the balcony to his death.

Aftermath
Anakin became Palpatine's second and final apprentice, Darth Vader. The Great Jedi Purge began.