No, the "rage boost" is what put him beyond Vader, temporarily. Sources have described them as perfect equals, in fact Luke managed to perfectly mirror Vader's lightsaber form just from encountering him a couple of times. He picked up a Form that would take anyone else decades to master, in seconds.
There are even some sources which imply Luke was holding back against Vader, while Vader was ready to kill Luke. I don't really subscribe to that theory, but if anything it only solidifies that Luke is at least Vader's equal.
Originally posted by ILS
Sources have described them as perfect equals, in fact Luke managed to perfectly mirror Vader's lightsaber form just from encountering him a couple of times.
Which sources?
I'm only going off by the movie but Luke suggests Vader is holding back by sensing his good and conflict within him. And if Luke didn't actually think Vader was holding back I doubt he would lower his defense and turn off his lightsaber completely.
It all hinges on the source though but unless it says explicitly that they are roughly the same in skill, which is plausible I admit, I'm not putting Luke on the level where he can easily take out veteran masters of the order just yet.
This is the source which suggests Luke was holding back.
When Luke confronted Darth Vader again, he possessed the clarity and wisdom of a Jedi Knight. He had no set out to conquer but rather to redeem the good in his father.Not to mention it's even said in the RotJ novelisation that Vader will kill if he has to, to paraphrase.Source: Lightsabers: A Guide to the Weapons of the Force
By the time of the Battle of Endor, Luke Skywalker has studied some lightsaber technique from Obi-Wan's journal and and greatly advanced his abilities. Without a Master, such advancement would have been impossible for most, but Skywalker's unparalleled aptitude makes him a match for Darth Vader in their fateful duel onboard the second Death Star. Both are limited, Vader by his cybernetic body parts and Skywalker by his relative lack of experience dueling. But Skywalker's skill at blaster deflection is highly refined, and his lightsaber technique so superb that he is able to duel the Dark Lord on even footing - and finally able to defeat a man who is a powerful living product of the ancient Jedi sword traditions from time immemorial. Such an achievement with little formal training is a testament to Skywalker's innate abilities and instinctive skill. Tremendously strong with the Force, Skywalker never crosses the line into Sith hatefulness and ceases his attack immediately upon rendering his foe helpless - an even more impressive demonstration of self-mastery than his lightsaber skills.Source: Insider #62: Fightsaber
In his final assault on Vader, Luke Skywalker mirrors Vader's own Form V technique and responds with a furious demonstration of Form V's raw strength. An observing Jedi Master would be astonished at such instantaneous learning in battle.Source: Insider #62: Fightsaber
The fight this time was far more balanced. Vader discovered that Luke was his match, and, once again, the Sith Lord found his thoughts straying to an alliance between them against the Emperor.
Luke had indeed grown powerful since Bespin, and he was an equal match for his father.Source: The Official Star Wars Fact File #111
On the Death Star, Luke and Darth Vader were engaged in a duel that was even more vicious than their battle on Cloud City. Luke had grown stronger since their last encounter, and his skill with his lightsaber had improved greatly. As they swung at each other in the Emperor's throne room, Luke sensed the advantage had shifted to him.Source: Return of the Jedi Junior Novelization
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