The trial over whether Led Zeppelin copied the iconic guitar riff in "Stairway to Heaven" from Spirit's "Taurus" may end abruptly, after a video shown Tuesday during opening statements sparked a discussion about a potential mistrial.

In previewing his case on behalf of Michael Skidmore, trustee for late Spirit songwriter Randy Wolfe, attorney Francis Malofiy played a video of a man with an acoustic guitar. The man, an unnamed expert, plays the beginning of "Stairway to Heaven" then the bass line of "Taurus," followed by both videos synched.

Led Zeppelin's attorney Peter Anderson objected to the video, claiming it wasn't included in the joint list of exhibits submitted prior to trial.

Malofiy didn't deny it but proceeded to play the video, despite technical difficulties.

U.S. District Court Judge R. Gary Klausner bluntly said if the video really wasn't in the joint exhibit list, its use would be "grounds for a mistrial." It remains to be seen if Anderson will move for a mistrial after day one.

'Stairway to Heaven' Trial: Judge Strikes Led Zeppelin Music Expert Request

Earlier in his opening statements, Malofiy said the case comes down to six words: Give credit where credit is due. He claims Wolfe wrote "Taurus," which fell "into the lovely hands" of Led Zeppelin guitarist Jimmy Page and became the iconic intro to "Stairway."

The "pink elephant in the room" -- as Malofiy described it -- is that the jury undoubtedly knows Led Zeppelin, Page and frontman Robert Plant. While Page and Plant are "incredible musicians" and "incredible performers," Malofiy says they're not songwriters and became famous by covering other bands' music and making it their own.

When Anderson took the podium, he pointed out that because this case is playing out decades after any alleged infringement, many witnesses have died and documents have been lost.

"Forty-five years ago, Jimmy Page and Robert Plant wrote some of the greatest songs in rock and roll history ... half a century later, they're being sued for it," Anderson said, adding that there is still enough evidence "to show that history cannot be rewritten."

He also laid out several defenses he intends to use including unclean hands, alleging the trust receives Wolfe's royalties because they were surreptitiously denied to his son. Even if the jury hears a similarity, Anderson says the use would likely be de minimus, derivative or composed of uncopyrightable musical building blocks. Anderson also says Spirit members often covered The Beatles and their 1965 song "Michelle" also uses a similar chord progression to "Taurus," which was published later.

After opening statements, the songwriter's sister Janet Wolfe and Spirit bandmember Jay Ferguson took the stand. Their testimonies were largely focused on Wolfe's status as a "prodigy" (he wrote "Taurus" at the age of 15) and when Led Zeppelin and Spirit performed on the same bill, presumably an attempt to show Page had access to Wolfe's song to hear it and later copy it. Neither witness could definitively say if "Taurus" was performed during the handful of events or if Led Zeppelin bandmembers saw the performance.

Skidmore, Page and Plant are expected to testify, along with Led Zeppelin member John Paul Jones, Spirit bassist Mark Andes and music producer Lou Adler.

This article was originally published by The Hollywood Reporter.