 He made his debut on 23 August as a 69th-minute substitute for Hugo Mallo in a 2–1 win at Levante, and scored his first goal on 23 September, a volley to confirm a 4–1 win over reigning champions FC Barcelona five minutes after entering as a replacement for Iago Aspas.On 27 January 2016, Guidetti scored with a 25-metre volley in a 3–2 win over Atlético Madrid in the quarter-finals of the Copa del Rey, helping his side reach the semi-finals of the Cup for the first time in 15 years.On 8 January 2018, Guidetti was loaned to fellow first division club Deportivo Alavés, until the end of the season.