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 squared 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.