on 3 july 2019, de tomás signed a five-year contract with portuguese champions s.l. benfica on a €20 million transfer fee. he debuted for the club as a starter in the 5–0 thrashing of crosstown rivals sporting cp in the supertaça cândido de oliveira on 4 august. he scored his first competitive goal for the side in a 1‒3 loss at fc zenit saint petersburg in the group stage of the uefa champions league, as a substitute; uefa ordered his shirt to say his legal surname for that match, while he habitually wore his initials instead.