What is the function of particle に in 「Aチームに[勝つ]【かつ】チームがあるとしたら…」?


I came across the following sentence

> Aチームに[勝つ]【かつ】チームがあるとしたら…  
>  If A team is the winning team...

Why is the に particle being used in `Aチームに`?  
Why would it not be `Aチームは` in this case?  
I have not come across an explanation on this usage of `に`.




First, your translation of the example is not correct, but that doesn't matter
with respect to what you want to know. The example means " **if there is a
team that beats Team A, then...** ".

The verb 勝つ has the
[valency](https://en.wikipedia.org/wiki/Valency_%28linguistics%29) が―に,
whereby が marks the subject, and に the object:

[code]

     subjectが objectに 勝つ
    
[/code]

The antonym of 勝つ is 負ける, which also has a が―に valency.

One famous explanation of verbs like these can be found _Shigeru Miyagawa_ 's
_Structure and Case Marking in Japanese_ (Syntax and Semantics vol. 22).




First, your translation of the example is not correct, but that doesn't matter
with respect to what you want to know. The example means " **if there is a
team that beats Team A, then...** ".

The verb 勝つ has the
[valency](https://en.wikipedia.org/wiki/Valency_%28linguistics%29) が―に,
whereby が marks the subject, and に the object:

[code]

     subjectが objectに 勝つ
    
[/code]

The antonym of 勝つ is 負ける, which also has a が―に valency.

One famous explanation of verbs like these can be found _Shigeru Miyagawa_ 's
_Structure and Case Marking in Japanese_ (Syntax and Semantics vol. 22).

