#3 Seth Rollins at Money in the Bank 2016
Roman Reigns' first true, clean loss on the main roster came at arguably WWE's best pay-per-view of 2016. After Rollins returned from his torn ACL at Extreme Rules, he challenged Reigns for his WWE title.
And although Rollins is a formidable foe, people probably didn't expect him to beat Reigns clean as a whistle in the middle of the ring. But that's exactly what he did.
Sadly, this may not have even happened if not for Reigns' violation of WWE's wellness policy. It was revealed the day after Money in the Bank that Reigns would be suspended for 30 days, which was the likely reason for WWE pulling the plug on what was expected to be a lengthy title reign after just a couple months.
But it did happen, and it was the beginning of Reigns finally becoming vulnerable. Whenever Reigns was in a singles match before this, it felt like there was no way he would lose clean, since he never had before.
But this match did a lot for his career, as it actually served to make his matches from that point forward more interesting. It was finally no longer a guarantee that the Big Dog would come out on top.