Cox recorded 11 strikeouts and three walks in the game for the Spartans, who scored their only run in the bottom of the sixth when Annie Monroe singled home Catherine Horner, who doubled and stole a base in the game.
The Spartans won their first two tournament games Saturday against Hart, 6-4, and host Woodbridge, 7-0.
Horner and Monroe combined for five hits and four runs batted in against Woodbridge. Alyssa Stolmack was three for three with two RBI in the win over Hart.
Arcadia 197, La Cañada 199: The Spartans were defeated for just the second time in this season Wednesday at Santa Anita Golf Course.
Colin Morikawa shared medalist honors, as he shot an even-par 36 for La Cañada (11-2). Joshua Suh also carded a 39 for the Spartans.
Lompoc 3, St. Francis 0: The Golden Knights began the Righetti Tournament on Wednesday with a loss. St. Francis (7-11) avoided being no-hit when Jeff Garavaglia singled with one out in the seventh.
Temple City 12, La Cañada 6: The Spartans dropped their second Rio Hondo League match this season without the services of No. 1 singles player Joshua Kim, who was competing in a national tournament, Tuesday.
La Cañada (6-4, 2-2 in league) got a pair of 6-2 wins from Andre Danuns in singles and two wins from Tyler Jones and Arthur Song (6-3, 7-6) and Lewon Lim and Joe Song (7-6, 6-1) in doubles.
Chadwick 17, Flintridge Prep 1: Teddy Willard and Michael Cassutt teamed up for a 6-3 doubles victory for host Flintridge Prep on Tuesday in a Prep League opener at Scholl Canyon Tennis Center. Flintridge Prep dropped to 3-7.