This is when Optimus fights Megatron in Weekenders Adventures of Transformers.

Optimus Prime: Megatron!

Megatron: Prime!

[He transforms into airplan and flies away but Optimus catches, as they smash through the building and landed on the ground, with Megatron on top of Optimus]

Megatron: Human don't deserve to live.

Optimus Prime: They deserve to chose for themselves.

Megatron: Then you will die with them! [his hand turn into a gun] Join them in extinction!!

[As the people watches them fight, Optimus gets out his gun and shoots Megatron, then he shoots Optimus into the building, as the people runs for their lives]

Optimus Prime: [groans]

Chase: Are you okay, Optimus?

Optimus Prime: I'm fine Chase.