"Maryland has only beaten Penn State once since 1961."
By placing the word "only" in front of the verb "beaten," it becomes a qualifier of that verb. The implication is that, even though Maryland has engaged in beating behavior once since 1961, they have engaged in other behaviors vis-a-vis Penn State. The way this sentence is constructed, it could continue as follows:
"Maryland has only beaten Penn State once since 1961, but Maryland has praised, cursed, admired, and licked the boots of Penn State many times since then."
C'mon folks, let's put "only" where it belongs, which is next to the word it is meant to qualify:
"Maryland has beaten Penn State only once since 1961."