A surprising favorite is emerging to become No. 1 contender for Brock Lesnar's WWE Universal title

The No. 1 contender will be decided in a Fatal 5-Way match at Extreme Rules.

The main event at this Sunday's WWE Extreme Rules show will feature a Fatal 5-way match for the No. 1 contender's spot at Brock Lesnar's Universal Championship, and it looks like a favorite for the winner of the match is starting to emerge.

According to SB Nation, former NXT Champion Samoa Joe has quickly become the betting favorite to win the match at Extreme Rules over Seth Rollins, Finn Balor, Bray Wyatt, and Roman Reigns.

Lesnar and Joe have never faced off before, so it would be a unique match up for the Great Balls of Fire show — yes, that's seriously the name, I don't know why — in July.

Joe winning the match would be an interesting choice by WWE, as he doesn't have a ton of momentum with his character ever since he was brought up to the main roster from NXT. However, WWE could use this opportunity to elevate Joe, as a competitive match with Lesnar for the title would certainly give him some credibility. Joe is a fantastic in-ring work, so he and Lesnar have the ability to tear the house down with a great performance; it all comes down to whether or not WWE let's that happen.

If it's not Joe, the next two favorites are likely Balor and Rollins. Balor technically never lost the Universal Championship last year when he won it (was forced to vacate) and Rollins is a guy that could put on a good match and wouldn't lose momentum with a loss.