Katsuhiko Nakajima
On February 11, 2014, Sasaki suffered his first loss to Katsuhiko Nakajima in the main event of a Diamond Ring event. Two days later, Sasaki held a press conference to announce his retirement from professional wrestling. Following Sasaki's retirement, Diamond Ring was left with only one remaining wrestler, Katsuhiko Nakajima, with Satoshi Kajiwara resigning and Mitsuhiro Kitamiya joining Pro Wrestling Noah.