Cody Rhodes unseating Roman Reigns as undisputed WWE universal champion at WrestleMania 40 immediately injected new life into the main event scene.

Reigns' stranglehold on the gold for the better part of the past four years prevented several Superstars from winning it and even contending for it due his title defenses becoming much more sporadic over time.

However, with Rhodes now set to be at the forefront on Friday nights, SmackDown is the land of opportunity once more.

A mini tournament kicked off on Friday's edition to determine Rhodes' first opponent, something that SmackDown hasn't featured in ages as a result of Reigns' rivalries mostly being storyline-driven. Having wrestlers earn their shot is a simple concept, yet a breath of fresh air for the blue brand.

It remains to be seen what show Rhodes and his new piece of hardware will be assigned to coming out of the 2024 WWE draft starting April 26, so it seems anyone from Raw and SmackDown can step up to challenge him for the foreseeable future.

These are the five best feuds for The American Nightmare as champ en route to SummerSlam 2024.

AJ Styles

Despite spending time in many of the same promotions over the last decade, Rhodes and AJ Styles have yet to wage war in one-on-one action.

That could change as soon as Backlash on May 4 if The Phenomenal One can beat LA Knight on SmackDown to become the No. 1 contender to the title.

It's a fresh feud with a ton of history available for them to tap into. Both men previously served as leaders of Bullet Club and became big stars elsewhere before achieving main event stardom in WWE.

Although the chances of Styles actually capturing the championship at Backlash are slim to none, his credibility makes him the perfect first challenger. He's a believable threat to the top title and can be counted on for a quality contest, especially with an opponent the caliber of Rhodes.

It's been years since The Phenomenal One was last slotted at the main event level, so expect him to make the most of the opportunity and push The American Nightmare to his limit.

A standout showing could be enough to earn Styles one last world title run down the road.

Kevin Owens

Kevin Owens came close to advancing in the mini tournament to determine the next Undisputed WWE Universal Championship challenger on the April 12 edition of SmackDown but ultimately fell short to Styles.

KO should get a crack at the gold eventually, though, given his own history with the current champ.

On an April 2022 episode of WWE's After the Bell podcast, Owens detailed his friendship with Rhodes dating back to 2016. The Prizefighter aided The American Nightmare in his rivalry with The Bloodline last year but was traded to SmackDown before he could team up with him in Survivor Series: WarGames.

It was in exchange for Jey Uso being traded to Raw, and considering Owens' checkered past with Uso from early in the Bloodline saga, it's safe to assume he may have had some resentment toward Rhodes for being shipped to the blue brand and abruptly breaking up his team with Sami Zayn.

As beloved as KO is at the moment, he has always been in his element as a heel. This would be a solid storyline heading into the King and Queen of the Ring event in Saudi Arabia on May 25.

Drew McIntyre

Per Mike Johnson of PWInsider, the latest word within WWE is that Drew McIntyre still hasn't re-signed despite his contract coming due in five to six weeks. That means it will expire just shy of Clash at the Castle on June 15, emanating from his home country of Scotland.

An extension must be signed to ensure he works that event in some capacity.

All signs point to McIntyre sticking around based on how he's been booked as of late, but if he does leave or at least take time off, WWE would likely want him to do the honors on the way out.

Putting over his current rival, CM Punk, would make the most sense, but if The Best in the World isn't cleared to compete in time, the Scot shifting his focus to Rhodes for that show in Glasgow would be a worthy consolation prize.

After all, McIntyre was the last person to pin Rhodes on the Feb. 19 edition of Raw, so acknowledging that could set up a major title clash between them for the summer.

They've already proved to have terrific chemistry in the ring, so a full-fledged feud could be equally entertaining.

Randy Orton

Randy Orton has perhaps been the most talked-about potential opponent for Rhodes as of late with The Viper being responsible in storyline for putting the new champ on the map over 15 years ago through The Legacy.

They exchanged wins in singles competition in late 2011, but a feud between them now would be on another level.

Rhodes cemented his status as one of WWE's top talents immediately upon his return to the company at WrestleMania 38, while Orton's long list of accolades speaks for itself. Pitting them against each other with the gold up for grabs would result in a huge marquee match, arguably even WrestleMania-worthy.

If Rhodes remains on the right track for a big-time bout with The Rock at SummerSlam, Rhodes vs. Orton would instead have to headline Money in the Bank or another event unless WWE holds off on it for later in the year.

Toronto, which will host Money in the Bank on July 6, would provide an excellent atmosphere for the highly anticipated encounter.

This rivalry is inevitable, so WWE may as well give fans what they want on the sooner side.

The Rock

In an Instagram post on April 14, The Rock heavily teased returning to the ring at WrestleMania 41 and that being where he gets his hands on Rhodes.

That seemed to confirm a recent report from the Wrestling Observer Newsletter that WWE intends to deliver that match at The Show of Shows next year.

An entire year is a long time to keep Rhodes waiting to renew that rivalry and give Rock his comeuppance after being beaten by him on Night 1 of WrestleMania 40. SummerSlam is the more appropriate place to book that bout, and that should be where it happens.

Any of the aforementioned Superstars would make fine opponents for The American Nightmare at the event, but none would give SummerSlam the same level of buzz and excitement as The Final Boss.

It would also guarantee progression on the Bloodline front and likely lead to whatever he has coming up with Roman Reigns, 22 years removed from The Great One's last SummerSlam match.

Graham Mirmina, aka Graham "GSM" Matthews, has specialized in sports and entertainment writing since 2010. Visit his website, WrestleRant, and subscribe to his YouTube channel for more wrestling-related content.