Warning! This article contains spoilers for the Obi-Wan Kenobi season 1 finale.
The Obi-Wan Kenobi season 1 finale featured the highly anticipated rematch between Darth Vader and Kenobi, with the latter coming out on top, physically and spiritually. The series up to this point has built to a rematch between the former brothers, with the finale offering up a bout of lightsaber action. Despite their brief confrontation in Obi-Wan Kenobi episode 3, a true rematch between the duo was the focal point of the final episode.
The Obi-Wan Kenobi season 1 finale follows on directly from Obi-Wan Kenobi episode 5, with Kenobi, Roken, Leia, and the other refugees fleeing the Empire and Darth Vader. Obi-Wan Kenobi, however, realizing that Vader only wants him, leaves in a drop-ship for a nearby planet. Vader takes the bait and follows Kenobi alone, leading to what seems to be the final confrontation between the two before the events of A New Hope.
Given the exceptional lightsaber fight between Obi-Wan and Anakin in Star Wars: Episode III - Revenge of the Sith, the excitement was palpable going into the confrontation. The fight in Obi-Wan Kenobi took place on a derelict planet surrounded by spires of rock, allowing for an equal amount of lightsaber combat and Force abilities to be explored. The fight took many different turns, with each combatant seemingly winning the fight at different points, but it was Kenobi himself who won the first Obi-Wan Vs Darth Vader rematch.
How Obi-Wan Beat Darth Vader In The Kenobi Finale
At a climactic point in the Obi-Wan Kenobi vs Darth Vader fight, Darth Vader unleashes his Force powers and sends Kenobi into a pit, before seemingly burying the former Jedi Knight under a mountain of stone. However, Kenobi, rather than accept defeat, finds his newfound strength that the series has been establishing since Obi-Wan Kenobi episode 1 and rounding off his character arc for the show. Kenobi has flashes of his adventures with Leia, as well as brief memories of Luke, and uses his need to protect Anakin's children as a means to find the strength to continue fighting.
Up to this point, Obi-Wan Kenobi has established Kenobi's need to balance himself within the Force and overcome his past trauma. In using Leia and Luke as a reason to do so, Kenobi's former strength returns and allows him to escape the pit, both literally and figuratively, and overcome Vader once more.
Why Didn't Obi-Wan Kill Darth Vader?
Much like Darth Vader avoids killing Obi-Wan in their first fight, it's worth noting that Obi-Wan doesn't kill Vader in the first Obi-Wan Kenobi vs Darth Vader rematch. Obviously, this would've been impossible, given what is known about the Star Wars timeline after Obi-Wan Kenobi. However, contextually within the story, it would have made sense for Kenobi to kill Vader, due to the former finally accepting that his padawan is gone and Vader is all that remains. Although in of Kenobi's character, it makes perfect sense as to why he didn't finish Vader. A lot of Obi-Wan Kenobi focused on his intense grief and guilt over what happened to Anakin after their duel on Mustafar. This guilt is likely a huge factor as to why Kenobi didn't murder Vader, not wanting to repeat his mistakes of the past.
Also, Kenobi is still a Jedi at heart, and Jedi were always taught to defend life rather than take it as reinforced in Obi-Wan Kenobi episode 5. Kenobi striking down Vader in cold blood would have gone against everything both he and the Jedi stand for. Also, it seems it was Vader himself who balanced Kenobi, by stating that the only person who destroyed Anakin was himself and that Kenobi shares no blame for this. Kenobi hearing this is what caused him to be at peace with himself finally, meaning he has no reason to kill Vader as he thought he may have to.
Could Darth Vader Have Won Their Rematch?
Given what is known about the future of Star Wars after Obi-Wan Kenobi, the question remains over whether the show could've portrayed Vader as winning the Obi-Wan Kenobi vs Darth Vader fight, despite the meeting between the two characters on the Death Star in Star Wars nine years in the future. There was certainly a way Obi-Wan Kenobi could have shown Vader to win the fight, without killing Kenobi - as at one point in the fight, Vader buries Kenobi and leaves, thinking the latter dead. It is through a scene like this that Vader could have been shown to win the confrontation. By having Vader think he had beaten Kenobi, Obi-Wan Kenobi could more than easily have shown Vader to win, only to be confronted by his former master once again in A New Hope.
However, it remains the case that thematically and emotionally, Kenobi was the only choice for the winner of the Obi-Wan Kenobi vs Darth Vader duel. In allowing Kenobi to overcome Vader, his character arc in Obi-Wan Kenobi comes full circle in a satisfying way that still makes Vader's "master" line in A New Hope make sense. This is a perfect setup, as it allows for an emotionally, narratively satisfying conclusion to the Obi-Wan Kenobi series.