Blac Chyna to Tyga All's Fair in Love and War

FIT FOR A KINGInstagram

Blac Chyna just one upped her baby daddy Tyga in the birthday department ... entertaining their son King Cairo and his friends for the boy's third birthday with a full-blown fair.

The party had all the trappings -- funnel cake stand, taco booth, face painting, water balloons, and not one, but 3 piñatas.

Christina Milian, Karreuche, and Bad Medina joined in for the fun.

BC thew her party a day after Tyga took King Cairo and his buddies go-karting.

And the winner ... King Cairo.