Sami Zayn defended his title tonight on SmackDown. He faced an unexpected opponent in an intense match.Sami Zayn has been on a roll since moving to SmackDown. After pinning Solo Sikoa on the August 15 episode of the blue brand, he earned himself a United States Title match two weeks later. Sami was able to defeat Solo Sikoa and win the US Title. Last week on the blue brand, Sami interrupted John Cena during the latter's segment and said he wants to relaunch the US Open Challenge. He also wanted Cena to be his first opponent. However, this match ended in a no-contest after Brock Lesnar came out and attacked both men.Tonight on WWE SmackDown, Sami Zayn's US Open Challenge continued as he defended his title against Rey Fenix. Rey took Sami to the limit during their bout that had the fans standing on their feet. In the end, Sami was able to successfully pull off a win over the former AEW star.Vince Russo believes Sami Zayn was rattled by the hostile crowd last week on SmackDownLast week on SmackDown, Sami Zayn interrupted John Cena and recalled how the Cenation leader gave him a huge opportunity to compete for the United States Championship back in the day. He also said he wants to do the same as US Champion, and so, he wanted Cena to be the first person to challenge him in the US Open Challenge.Speaking on a recent edition of BroDown with host Mac Davis, Vince Russo stated that Sami was rattled by the hostile Chicago crowd, who were booing him during his segment. Hence, he started pandering to the fans."Yeah, bro, I swear to God, if you go back and watch this, Mac, your boy, Sami, was getting rattled by the viewers. We ain't in Paris, Sami, we ain't in freaking Paris. We're in Chicago. And he was getting freaking rattled, and he so had to go the other way. 'Oh, these people--' Okay, alright, bro."It will be interesting to see who will be next in line to challenge Sami for the United States Championship.