Masayuki Kono
On July 10, 2013, Funaki was announced as part of Keiji Mutoh's new Wrestle-1 (W-1) promotion. During the promotion's inaugural event on September 8, Funaki teamed with Masayuki Kono in a tag team match, where they were defeated by Katsuyori Shibata and Kazushi Sakuraba. Following the match, Kono turned on Funaki, hitting his mentor with a steel chair. Funaki and Kono faced off in a singles match at Wrestle 1's second show on September 15, where Kono was victorious with help from Kazma Sakamoto and Ryoji Sai. A rematch between the two took place on October 12 and saw Funaki emerge victorious. On March 2 at , Funaki defeated Total Nonstop Action Wrestling (TNA) representative Bobby Roode in an interpromotional match, after which he challenged Olympic gold medalist Kurt Angle to a match. At Wrestle-1's July 6 event, Funaki defeated Pro Wrestling Zero1 (Zero1) representative Kohei Sato to win the World Heavyweight Championship. He lost the title back to Sato on September 19. Three days later, Funaki entered the Wrestle-1 Championship tournament, defeating Tajiri in his first round match. The following day, Funaki defeated Akira to advance to the semifinals of the tournament. Prior to the semifinals of the tournament, Funaki entered a storyline, where his former rival Tajiri came to his aid to help him prepare for his match. On October 8, Funaki was eliminated from the tournament in the semifinals by Masayuki Kono, after Tajiri turned on him. In June 2015, it was announced that Funaki would be leaving Wrestle-1 and going freelance following his contract expiring at the end of the month. His final match for the promotion took place on June 20.