Complex sentence: He went on to score six goals in his next ten games for Celtic, before netting a hat-trick on 15 April after coming on in the second half of a 4--1 win in the league over Kilmarnock.
Split into simpler sentences: He went on to score six goals in his next ten games for Celtic. Griffiths netted a hat-trick on 15 April after coming on in the second half of a 4--1 win in the league over Kilmarnock.