Leaders China, US fight hard for 3-2 win, to meet on Monday
Blocking was also an important factor behind China's sixth consecutive win, as the defending champions outperformed their opponent 17-7 with Yuan contributed seven kill blocks alone.
China will next face the United States, the only other team yet to lose a match, who also needed five sets to edge host nation Japan 26-24, 22-25, 25-21, 23-25, 15-8 late on Sunday night.
Michelle Bartsch-Hackley scored 30 points for the Nations League champions, which rotated its starting line-up and benched captain Jordan Larson and opposite hitter Karsta Lowe. Mayu Ishikawa and Yuki Ishii had 23 and 21 points each.
"Congratulations on Japan, they played very good volleyball and that's no surprise," USA coach Karch Kiraly said of the tenacious Japanese side that tied the match twice. "We always expect it will be very difficult to play against Japan because they play with such great defense and a great heart."