Saturday's UFC 306 card will mark the promotion's debut in the Las Vegas Sphere, and it's expected to be one of the most expensive, entertaining shows in its history.

In fact, UFC President Dana White has gone so far as to say the venue will be the star of the show.

That, of course, won't be the case. The fighters will always be the stars of the show when it comes to UFC events, and there are some big names on this Saturday's bill, most notably in the top two contests.

The headlining spot will go to a bantamweight title fight, with champion Sean O'Malley taking on surging No. 1 contender Merab Dvalishvili.

There will also be a title up for grabs in the co-main event, when flyweight champ Alexa Grasso defends her belt against former titleholder Valentina Shevchenko in what should be the final installment of a three-fight rivalry.

Earlier on the card, we'll get a fan-friendly featherweight contest between Brian Ortega and Diego Lopes, which was originally set to occur at UFC 303, and appearances from a number of Latin American prospects.

Keep scrolling for the biggest and best fights on the bill for the UFC's long-awaited debut in The Sphere.

Sean O'Malley vs. Merab Dvalishvili

Sean O'Malley had plenty of doubters as he climbed the bantamweight ladder, but he proved them all wrong last year by knocking out long-time champ Aljamain Sterling to claim the division's undisputed title.

The 29-year-old has defended the belt once since, avenging the only loss on his record with a lopsided decision win over Marlon "Chito" Vera, and he will look for a successful second defense opposite Merab Dvalishvili at UFC 306.

It will be the toughest test of his career.

Dvalishvili, 33, has won 10 straight fights in the UFC bantamweight division. That streak, which is the longest in the weight class' history, includes recent victories over former champions like Jose Aldo, Petr Yan and Henry Cejudo.

While O'Malley is known for his pinpoint striking and knockout power, his Georgian opponent is known as a relentless wrestler with great takedowns and suffocating ground control.

This fight may be a bizarre choice for a card that is intended as a celebration of Mexico's combat sports history, but it's an excellent style clash that the oddsmakers think could go either way.

It will also give us a firm answer as to who the best bantamweight on Earth is.

Alexa Grasso vs. Valentina Shevchenko III

When Alexa Grasso first challenged Valentina Shevchenko for the UFC flyweight belt early last year, she was expected to suffer the same fate as most of Shevchenko's other opponents and get whooped.

That's not the way it happened.

Instead, the former Invicta champ authored one of the biggest upsets of the year, tapping Shevchenko with a rear-naked choke to win the belt.

Months later, the 36-year-old was granted an immediate shot at redemption on the basis of her long-time dominance. Unfortunately, the five-round sequel with Grasso provided little in the way of closure, ending with a majority draw.

A trilogy fight has been imperative since the pair left the cage after their second clash. While it was delayed while the pair served as rival coaches on The Ultimate Fighter—allowing a long list of deserving flyweight title challengers to form—they will finally look to settle their rivalry at UFC 306 in the first trilogy in the history of the UFC women's divisions.

It's hard to say who will come out on top, but it's bound to be another great fight and will allow the stacked UFC flyweight division to continue moving after over a year of stasis.

Brian Ortega vs. Diego Lopes

Diego Lopes is one of the hottest contenders in the UFC featherweight division, and he was expected to get a huge step up in competition in the form of former title challenger Brian Ortega at UFC 303 in June.

Regrettably, the fight fell through when Ortega suffered a last-minute illness.

Lopes was then matched up with Dan Ige on short notice. Soon after he defeated the American by decision, it was announced that he had been rebooked for a fight with Ortega for Saturday's show at the Sphere.

Nobody complained when the matchup was rebooked.

Lopes and Ortega are cut from the same cloth. Both are high-level BJJ black belts, with slick submissions, and both back up their grappling prowess with underrated striking and knockout power.

Ortega, 33, who has twice contended for the featherweight belt to no avail, may be getting on in his career, but he is still a top talent, as he proved in his recent win over Yair Rodriguez.

This matchup has Fight of the Year potential, and it could well produce the next challenger for the winner of the upcoming featherweight title fight between Ilia Topuria and Max Holloway.

Raul Rosas Jr. vs. Aoriqileng

Raul Rosas Jr. might be the hottest prospect in the UFC.

While the 19-year-old suffered a hype-deflating decision loss to Christian Rodriguez in his second UFC appearance, he has since responded with a pair of victories over Terrence Mitchell and Ricky Turcios—both finishes.

He will look to take another important step in his career when he takes on Aoriqileng in the opening bout of Saturday's Sphere card.

If Rosas is victorious, he will probably only be a win or two away from a fight with a ranked opponent. However, the 31-year-old Chinese veteran is not going to make it easy for him.

Aoriqileng has been hot-and-cold in the UFC, but he has nearly 40 pro fights to his credit, including scraps with top-flight opposition such as Kai Kara-France, Cody Durden and Aiemann Zahabi.

In truth, Rosas Jr. should win this one, but it also shouldn't be a cake walk. One way or the other, it's going to tell us a lot about what the future holds for the bantamweight super prospect.

It's a great opener for the card, and it's actually one of the best fights on the bill.

Daniel Zellhuber vs. Esteban Ribovics

The UFC 306 main card will feature appearances from two of the top Latin American lightweight prospects on the UFC roster: Mexico's Daniel Zellhuber and Argentina's Esteban Ribovics.

Both men have only lost once, and both have proved they can finish fights anywhere.

Zellhuber has seven wins by knockout or TKO and three by submission, while Ribovics has seven wins by knockout or TKO and five by sub. In other words, both men are very good, and their main card scrap could finish at any moment, from any position.

The winner still won't be ready for a top-15 foe, but both guys are under 30 and have tons of time to evolve into serious title contenders.

No matter what the future holds, their Saturday fight should be a lot of fun, and it's very unlikely it goes the distance.