Complex sentence: Milan fell away, instead focusing their efforts on the European Cup, and it seemed that Cagliari would retain top spot, but after losing against Juventus, Fiorentina took over at the top.
Split into simpler sentences: Milan fell away, instead focusing their efforts on the European Cup, and it seemed that Cagliari would retain top spot. After Cagliari lost against Juventus, however, Fiorentina took over at the top.