Complex sentence: The first match played in Celtic Park was on 4 May 1958, a challenge game between Castlebar Celtic and Castlebar A. The first competitive game in the ground was between Castlebar Celtic and Westport United the following Sunday, in the Mayo Area Final of the Connaught Cup.
Split into simpler sentences: The first match played in Celtic Park was on 4 May 1958. This was a challenge game between Castlebar Celtic and Castlebar A. The first competitive game in the ground was between Castlebar Celtic and Westport United the following Sunday, in the Mayo Area Final of the Connaught Cup.