Shingo Takagi
After this, Tanahashi began feuding with the newly formed United Empire. At Wrestle Kingdom 15 Night 1, he defeated Great-O-Khan. At The New Beginning in Nagoya, Tanahashi defeated Shingo Takagi to win the NEVER Openweight Championship for the first time. At Castle Attack, Tanahashi retained the title in a rematch with Khan, which was his only successful title defense. After being eliminated in the New Japan Cup tournament by Jay White, he started challenging Tanahashi for a title match. At Sakura Genesis 2021, Tanahashi teamed up with Satoshi Kojima to defeat White and Bad Luck Fale in a tag team match. On the first night Wrestling Dontaku 2021, Tanahashi lost the title to Jay White in the main event, ending his reign at 93 days. On July 25, it was announced that Tanahashi would face Shingo Takagi at Wrestle Grand Slam for the IWGP World Heavyweight Championship after Kota Ibushi was unable to compete. At the event, Tanahashi lost to Takagi.