Is there an Ancient Greek equivalent to the Latin phrase “excelsior?”

Ioannis Stratakis is right, but the cultural equivalent that I can think of is Homer’s αἰὲν ἀριστεύειν καὶ ὑπείροχον ἔμμεναι ἄλλων (Iliad 6.208): “always to excel, and to be superior to others”.