In the 1899–1900 football season Gillespie scored 8 goals and was City's third highest goalscorer. The team finished in seventh place that season. Gillespie's first goal in the top tier of English football came in a 4–0 victory over Derby County. In the 1900–01 season Gillespie found his place in the team challenged by Joe Cassidy who was the team's leading goalscorer with 14 goals that season. However Cassidy moved to Middlesbrough after a wage dispute. Gillespie had managed to score 9 goals in 23 appearances that season.