In the 2019–20 Copa del Rey, Oyarzabal scored a penalty in each leg of a 3–1 aggregate defeat of CD Mirandés as his team reached the final for the first time since 1988. On 10 July that year, he achieved his 50th goal for the club in a 3–2 home defeat against Granada, and on 3 October while still 23 he scored a penalty in his 200th match in a 3–0 win over Getafe CF.