My tennis partner says correcting her out call was disloyal. What should I say before our next match?

At 5–5, my doubles partner called a rally ball out. I saw it catch the line and said, "I had that in." We conceded the point. Afterwards she told me, "You could have talked to me quietly instead of embarrassing me."

This was a USTA league match without an official on our court. The [USTA's explanation of partners disagreeing on a call](https://www.usta.com/en/home/improve/tips-and-instruction/national/the-ad-inbox-mailbag--get-answers-to-your-tennis-questions.html) says the ball is good when one partner calls it out and the other calls it good. I don't want to leave a call I believe is wrong simply because it's an important point.

I also said it sharply. She'd already been struggling, and I can see why it sounded like I was correcting her as a person. We have another match together next week.

What would help us agree on how to handle a disagreement promptly, while keeping the call accurate and giving neither partner a reason to stay silent?