Kuznetsova, who had already qualified for the semifinals, finished the round robin with a 2-1 record. Muguruza had already been eliminated and ended up with a 1-2 record.
Kuznetsova was the last player to qualify for the season-ending tournament. She will play Dominika Cibulkova (1-2) in the semifinals on Saturday.
The second semifinal spot from the group will be decided later Friday when defending champion Agnieszka Radwanska (1-1) plays Karolina Pliskova (1-1). The winner of that match will face top-ranked Angelique Kerber in the semifinals.