Senior won the 1936 California State championships over a young Joe Hunt, displaying "swift, steady, well-planned tennis".

[2] He won the Illinois state title over former US champion Wilmer Allison in three straight sets for the loss of just three games.

[3] Senior won the Michigan State title beating George Toley in the final in four sets; his forehand drives gave him control of the match.

Senior "varied his long-hitting game with drop shots and clever cuts and at one stage of the last set he took 15 straight points".

"He drove his shoulder-high forehand with blazing speed, backhanded placements down the sidelines and showed nice judgment of lobs.