A federal appeals court panel in San Francisco appeared skeptical of Alphabet Inc.’s argument that its competition with Apple Inc. in smartphones is sufficient to justify overturning a jury verdict that declared an illegal monopoly for Android apps.

Lawyers for Alphabet's Google and "Fortnite" maker Epic Games are set to square off before a U.S. appeals court in California on Monday, as Google tries to undo a jury verdict and a judge's order forcing it to revamp its app store.

Ellsworth told the appeals court that U.S. District Judge James Donato improperly allowed Epic to turn the Google trial into a “do-over” that excluded the Apple app store as a rival in the market definition that led to the jury’s verdict in its case.