The second sentence is exactly how a native would phrase it, especially for a very polite apology.
The first sentence has bad implications. Unequal terms implies something outside the game has rigged the game. There are a milllion different ways of saying "Their team was really good, but my team was shit". Sports commentators say that same phrase a different way every week. But for you, I would make use of the phrase "part of it". It's a good way to make it clear that an issue has multiple parts. In this case you would say "Part of it was that your team was good, but the other part of it was that my team plYed like shit".
As a Liverpool fan after last year, I was saying that last sentence a lot.... our goalie man..