Masters and Students

Star Wars: The Transformers Wars episode 18 is where Optimus Prime first cross swords with Darth Grievous.

Episode Summary
After repairing the damages at both Mon Calamari and Tatooine the Autobots made a spearhead attempt to capture the leader of Darth Grievous's Sith Legion... Darth Grievous. The Autobot Jetfire scanned a C-17 Globemaster to Transport Autobots and Autobot Intelligence had traveled to Kalee and Korriban to find the wereabouts of Darth Grievous. Optimus Prime and Silverbolt lead a force of Jedi to Kalee because Silverbolt first meet Darth Grievous there while the Breakaway and Skyfire lead a group of Autobots to find the Seekers at Korriban. Optimus Prime found Darth Grievous at Kalee helping the Kaleesh warlords get revenge against the Jedi and the Autobots. The Battle at Kalee begins as Darth Grievous and his Kaleesh Comrades defeated a number of Huk and Jedi thus leaving Silverbolt and Optimus Prime against Darth Grievous. Darth Grievous pulls out his lightsabers and gogt into a lightsaber fight with Optimus Prime and Silverbolt. The Lightsaber fight was so intense that Optimus Prime got injured in the fight thus leaving only Silverbolt left to fight Darth Grievous until more Autobot Reinforcements have arrived. Before Silverbolt can impale Darth Grievous the evil Sith Lord teleports to Korriban by wrapping himself with his cape. Optimus Prime was taken by the Jedi and Silverbolt to the Venator Star Destroyer the Ark for repairs. Meanwhile the Autobots that are traveling to Korriban realized there are to many forces stationed there so they call off the attack. Optimus Prime was taken back to Cybertron to replace his broken cosmotron with a new one. The Autobots realized that more Star systems were being under siege by Darth Grievous's evil forces and the Autobots and the Jedi are preparing to make a hyperspace jump to help out those Outer Rim Territories.