Destroy his nonmagical armor. With Web and blind the wizard could then beat the barbarian by stabbing with a knife or sling. No studded leather + a -4 to dex from entangled + a -2 from blind means an ac of 7 or less if barbarian is raging. This gives a wizard 75% chance of hitting wit nearly anything. It's more about embarrassing with wasteING spells in inefficient ways.