Maybe if we hit him with a REALLY big stick.

Well I have now made a judgment based on my knowledge of Dragon Ball Z and Slayers. The main question was, who would win, Lina or Goku. There are several ways they could fight, I have some ways detailed here. Well in this case we are going for a power struggle. Dragon Ball Z is known for the greatest, largest, pointless, raw POWER in all of anime. Slayers is considered, by far, a much better series but within its storyline it has access to a source of power that could be looked upon as the will of One God itself.
A little background on Slayers. The main character, Lina Inverse, has relatively easy access to the greatest spell in black magic(magic based around destruction) of all time. The Giga Slave. It ruins the plot a little, but I will tell you that the Giga slave is not actually a spell as spells are normally in slayers (invoking some god’s power) that the Giga slave is actually summoning the God of destruction and asking it to eliminate something from existence. If One God was composed of a lord of creation and a lord of destruction in a delicate equilibrium maintaining existence as we know it, the Giga slave would be asking the Lord of destruction part to do your bidding.
A little background on Dragon Ball Z, incase you’ve been intelligently sheltering yourself from it. The main character of DBZ, Goku, spends the entirety of the series gradually becoming more powerful until at the end becomes a God. All of DBZ works like this, “…..well, it’s time to res- AH an even BIGGER more POWERFUL bad guy who wants to blow up the earth for no good damn reason, we must defend it at all costs!”
“AHHH- every fucking person is dead except for Goku and the planet has been ass raped again.”
“Ha! Goku is almost dead, and OH he pulls tons of power out of his ass and kills the bad guy.”
“Everyone comes back to life, well it’s time to res-“
It works kind of like American cartoons, “Lets keep producing shows until they kick us off the air!” Shitty plot, no character development, nothing really interesting, cosmic or important, an embarrassment to the rest of what anime stands for. Perfect for American television.
But that’s beside the point.

Examining the sheer power of Goku, and the sheer power of the Lord of destruction. It would be a deadlock. However, if Goku and Lina fought. And lina used a Giga slave, something that not even the Lord of destruction nor the Lord of creation could control, would happen. Between the Layer that separates Story Universes, and the Layer that the Dimension Matrix that Goku and Lina were fighting equally on exists Laws that operate the Dimension Matrixes. These are Anime Laws.
Goku would survive the Giga Slave. The reason he would survive the Giga Slave is that he is a god exactly as the Lord of Destruction. Normally two opposing forces of equal power would cancel each other out. However, DBZ’s laws and Slayers laws conflict here. An even deeper conflict would occur between the horribly shitty plot of (and its twisted anime laws) Dragon Ball Z, and the deep, cosmic, emotional, and fundamental plot (and its well planned laws) of Slayers. While this is a Power struggle and not a Plot-wise characters are flavored by their stories and the effect carries over some. What would happen is that Goku would survive but his surviving would cause the balance of destruction and creation to be thrown off in this Dimension Matrix and alter the Story Universe so that it is impossible to even DETECT by anyone except for the Lord of story.
The explanation to why no one could detect it is that an imbalance in creation and destruction would not destroy the Dimension Matrix. It would do several things, one it would alter the existence inside of it so that no forces inside of it could understand or affect the new existence. Also it would change the Story Universe so that we could not recognize its existence as we are only able to perceive our current balance of creation and destruction. It wouldn’t destroy them; it would just change their form of existing to something that we could not understand.
Also, just for your information, I don’t like Dragon Ball Z, I hate them. I love slayers, but Goku, is unstoppable. These are just my opinions and i realize that the true answer is beyond me. You could look at this from a million different ways and come up with any solution to fit your own desires, but i think this answer does justice to both series and their respective power.

What twisted creature came up with this GOKU person anyway?