Complex sentence: The club also competed in two consecutive seasons of UEFA Cup--in 1996, they were knocked out in the second round, while in the 1998, they managed to reach the third round, losing to Atlético Madrid 2--1 on aggregate score.
Split into simpler sentences: The club also competed in two consecutive seasons of UEFA Cup. In 1996 they were knocked out in the second round, while in the 1998 they managed to reach the third round, but lost to Atlético Madrid 2--1 on aggregate score.