Answer: opponent

AnswerCrossword Clue
OPPONENT

Frazier, to Ali

OPPONENT

Yankees, to the Red Sox

OPPONENT

Rival

OPPONENT
Adversary
OPPONENT
Antagonist
OPPONENTFoe
OPPONENTAdversary.
OPPONENTAli, to Frazier at Manila
OPPONENTTilden, to Hayes
OPPONENTOther side
OPPONENTSchmeling, to Louis
OPPONENTCounter person
OPPONENTOne from the other side