  In this paper, we prove common fixed point results for a self-mappings
satisfying an implicit function which is general enough to cover a multitude of
known as well as unknown contractions. Our results modify, unify, extend and
generalize many relevant results of the existing literature. Interestingly,
unlike several other cases, our main results deduce a nonlinear order-theoretic
version of a well-known fixed point theorem (proved for quasi-contraction) due
to \'{C}iri\'{c} (Proc. Amer. Math. Soc. (54) 267-273, 1974). Finally, in the
setting of metric spaces, we drive a sharpened version of Theorem 1 due to
Berinde and Vetro (Fixed Point Theory Appl. 2012:105).
