I've found at lower leagues, nothing whatsoever can beat mass carrier 
Either they don't have proper defences/they don't know what to do and auto attack the interceptors/don't have enough stalkers-hydras-etc.
Amass a fleet of 8-12 carriers, research gravitational catapult, build interceptors and off ya go.

Either they don't have proper defences/they don't know what to do and auto attack the interceptors/don't have enough stalkers-hydras-etc.
Amass a fleet of 8-12 carriers, research gravitational catapult, build interceptors and off ya go.

