Complex sentence: He is most credited for signing fans' idol Ľubomír Moravčík during his season as manager, as well as inflicting a punishing 5--1 defeat on arch-rivals Rangers in the first half of the season.
Split into simpler sentences: He is most credited for signing fans' idol Ľubomír Moravčík during his season as manager. The stand-out of his reign came as his Celtic side inflicted a punishing 5--1 defeat on arch-rivals Rangers in the first half of the season.