Betting anything in a 15 leg parlay isn't "unlucky" if it loses. It's lucky it went 14-1(13-1 really considering the void). There is a reason the odds are like that. I don't know tennis well, but I do know that favorites lose in it seemingly more than any other sport I've ever seen. If you're going to parlay tennis, I'd cut it way back from 15, even on just for fun plays. It's just a very inconsistent sport. As I said above I think you got extremely lucky to have just 1 leg lose in that. I avoid tennis like the plague. When I didn't know what I was doing I once hit 2 10 leg soccer parlays in a week time frame. I know nothing of soccer, it was all slight home favorites with some of them as no draw bets. I did maybe 10 more of them over the next few weeks, and never won again, but came close in some 6-8 legged ones (1 game lost, like yours). I quickly saw that I didn't get unlucky by losing the next 10 of them, I just got extremely lucky to even hit the 1, much less 2 in a week. It does suck to see your slip and see only 1 loss though, I understand what you mean but it was lucky to lose just 1. Maybe try some smaller ones, like 5 legs? See if that profits over time.