Complex sentence: Korda also was a part of the Czech Republic's team which won the Hopman Cup in 1994, and he upset defending champion, Pete Sampras, in five sets in the fourth round of the 1997 US Open.
Split into simpler sentences: Korda also was a part of the Czech Republic's team which won the Hopman Cup in 1994. He also upset the defending champion, Pete Sampras, in five sets in the fourth round of the 1997 US Open.