Complex sentence: Their best European performance to date was reaching the quarter-finals of the Inter-Cities Fairs Cup in 1962--63: after eliminating Spartak Brno (Czechoslovakia) and Leipzig XI (German Democratic Republic), they were finally defeated by the Hungarian side Ferencvárosi TC.
Split into simpler sentences: Their best European performance to date was reaching the quarter-finals of the Inter-Cities Fairs Cup in 1962--63. After eliminating Spartak Brno (Czechoslovakia) and Leipzig XI (German Democratic Republic), they were finally defeated by the Hungarian side Ferencvárosi TC.