elbow to elbow (in close proximity, side by side) · neck and neck, nip and tuck (so evenly matched that the advantage shifts from one to the other, and the outcome is uncertain)
köken: A rhyming phrase. The first word is perhaps from nippa, nipukka, nipistää, while the second may be from the first or from dialectal nappi (“scarce, scanty; narrow”), from Swedish knapp.