How to say "歪打正着“ in English? How do you say "歪打正着“ in English?

I brought a gift to someone's place for appreciation of his help, but he wasn't there. Several days later, I went there with the gift again, and he was there, and that day happened to be his birthday. So the gift happened to be also for his birthday celebration

So in Chinese, it is kind of "歪打正着“. How would you say it in English for such an example?
You could also call that... serendipitous!