Fernandes scored his 23rd competitive goal of the 2018–19 campaign. This was during a 3–1 home win against Portimonense S.C. on 3 March 2019, through a late penalty. He beat António Oliveira's club record for goals by a midfielder in a season. This was set in 1981–82. On 5 May, he scored a hat-trick in an 8–1 away win against Belenenses SAD. He became the highest-scoring Portuguese midfielder in a single season ever, with 31 goals to his name. He scored his 33rd and final goal of the season on 25 May 2019. This was during Sporting's win against FC Porto in the Taça de Portugal final. He was named Primeira Liga Player of the Year for the second year, in the 2018–19 season.