Tabatabaei competed in the Asian Chess Championship in December 2018. He finished second on 6½/9 (+4–0=5), and thus qualified for the Chess World Cup 2019. He won the Biel Masters in July 2019 with 7/9 (+6–1=2) and Josef Kupper Memorial in August 2019 with 6/7 (+5–0=2). At the Chess World Cup in September, he defeated Bassem Amin in the first round, then was eliminated by Jeffery Xiong in the second round.