Pedzisa mutsara unotevera: Yamaguchi akakwikwidza somunhu ane makore gumi nemasere uye nhengo yeboka reJapan mumitambo miviri yefreestyle relay pa2008 Summer Olympics muBeijing. Pasinei nokurasikirwa nenzvimbo yega yega mumamita mazana maviri akasununguka, akakwanisa kutora nzvimbo yechina mumitambo yeOlympic muTokyo (2: 01.64) kuti awane sarudzo yakananga pachikwata chevarwi. Kubatana naHaruka Ueda, Maki Mita, naEmi Takanabe mu
4 × 200 m freestyle relay final, Yamaguchi akahwina muchikamu chechipiri ne 1:58.51, asi chikwata cheJapan chakafanira kugutsikana nenzvimbo yechinomwe mu 7:57.56. Yamaguchi akapindawo mumakwikwi e4 × 100 m freestyle relay, pamwe chete naUeda, Mita, naAsami Kitagawa, asi akatadza kupinda mumakwikwi e8 epamusoro ne0.08 yechipiri munguva yekutanga ye3:39.25.