Star Wars #37 and Titans #43

Between the Star Wars and The Empire Strikes Back movie adaptations, Marvel Comics used Darth Vader sparingly.  In fact, the Dark Lord of the Sith did not see his first comic appearance after Star Wars #6 outside of flashbacks to the events from the movie until Star Wars #21, when we learn it was his mind touching Luke Skywalker's mind that put Luke into the coma.  Vader would appear a few more times during the Wheel saga.  Afterwards, Darth Vader showed up to dispatch Valance the Hunter in Star Wars #29.  In Star Wars #35, Darth Vader learns the name of the pilot that destroyed the Death Star, Luke Skywalker.  In Star Wars #36, Luke Skywalker and Darth Vader meet face to face for the first time.  And in Star Wars #37, we finally get to see Luke Skywalker battle with Darth Vader... sort of!

Star Wars #37a - Marvel Comics, U.S. (July 1980)

The cover to Star Wars #37 shows Luke Skywalker standing in the shadow of Darth Vader.  They are in a clearing in Crystal Valley on the planet Monastery.  Both warriors are poised to have a lightsaber duel.

Titans #43a - Editions Lug, France (August 1982)
Star Wars #37

The cover for the French Titans #43 shows the two opposing warriors engaged in battle.  This scene takes place moments after the cover to Star Wars #37.

Despite the excitement a Luke Skywalker versus Darth Vader battle elicits, it turns out that Luke is not actually confronting Vader, but Baron Orman Tagge, a longtime nemesis to our star warriors in the Star Wars title.  Darth Vader projects an illusion of himself onto Baron Tagge who Luke dispatches during the battle.  Darth Vader explains he rids himself of a rival in Baron Tagge, but also tests Luke Skywalker to learn how adept he is at using the Force.  It is a standard comic trope to have a misleading cover and that cliche is used effectively here.  It did not make sense for Marvel to have the first real Luke Skywalker versus Darth Vader lightsaber battle, as The Empire Strikes Back was a month away from being released to theaters.  Of the two covers, the cover to Star Wars #37 does a better job of portraying the importance of the conflict, but also hinting that things are not necessarily as they seem.