Limit a foe's sight range. It is easier to hit, and the creature will miss more often.
Attack rolls against it have Advantage and the foe attacks with Disadvantage.
If it is higher level than the spell slot you used to Counterspell, you must make a check using your spellcasting ability[See Notes] to prevent it. The check's difficulty is equal to 10 plus the level of the spell you are trying to counter.