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Baseball just has "errors." Tennis has "unforced errors." American football has fumbles, interceptions, safeties, and lots of ways to draw a penalty. I'm probably leaving out other bad things you can do, too (hiking it over the punter's head, or stepping out of bounds, for instance).

I think if we're using it in a non-sports context, "own goal" and "unforced error" are both appropriate.

I thought they were using tennis analogy, where player hitting the ball out or on the net without being forced to by the opponent counts as an unforced error.

Baseball doesn't distinguish between forced and unforced errors: a ball put in play that results in a baserunner is either a hit or an error. The forced/unforced distinction comes from tennis as far as I know.