The Ultimate Fighting Championship returns to Madison Square Garden on Saturday with what is perhaps its most loaded card of 2021, an event that features two championship fights and a No. 1 contender identifier for the promotion’s most competitive division.

The pay-per-view, sold in the United States by ESPN+, begins at 10 p.m. Eastern and costs $69.99.

Here are the things you need to know about the most important bouts on the card:

Kamaru Usman vs. Colby Covington

Kamaru Usman became the welterweight champion in 2019 after defeating the former champion, Tyron Woodley, via decision. Since then, he has defended the belt four times, finishing three fights by knockout.

His first title defense came against Colby Covington in 2019, a competitive five-round battle that ended in the last round when Usman landed shots to Covington on the ground that compelled the referee, Marc Goddard, to end the bout. Covington contends that the stoppage was early because he claims he was defending himself, and he also accused Usman of exaggerating his reactions to a kick close to the groin and an eye poke that caused Goddard to pause the fight twice.

The two men genuinely dislike each other, as evidenced by the insults they have hurled at each other and heated broadcast interviews they participated in. Covington in particular has been brash, latching himself onto the former President Donald J. Trump, wearing “Make America Great Again” hats and promoting Donald Trump Jr.’ s book.

In the cage, Usman is the more muscular man, but Covington absorbed most of his punches well during their last fight. To win, Covington will need to use his cardio advantage and set an aggressive pace while also varying his attacks between striking and wrestling. Usman is a more well-rounded fighter and is a -300 betting favorite. His light, straight jabs hold enough power to send a person to the ground. He could win in a variety of ways, but will likely attempt to use his reach advantage to keep Covington at a distance.

Rose Namajunas vs. Zhang Weili

Rose Namajunas stripped Joanna Jedrzejczyk, who at the time had dominated the women’s strawweight division, of the title in 2017 via technical knockout. She lost the belt in 2019 but regained it in April, when she head-kicked Zhang Weili, her left foot tapping Zhang’s chin and sending her to the ground. Zhang, once up, contested the stoppage.

Zhang became the first Chinese champion in U.F.C. history in 2019, and her defeat to Namajunas was viewed as a quick end to what should have been a competitive, fast-paced fight between the world’s best 115-pounders. Since the loss, Zhang began training with Henry Cejudo, the former U.F.C. flyweight and bantamweight double champion. Namajunas will most likely use her reach advantage and superior striking, while Zhang will look to grapple in the clinch.

Justin Gaethje vs. Michael Chandler

This is essentially an audition for the next opponent for the U.FC.’s lightweight championship. With the 155-pound champion Charles Oliveira scheduled to fight Dustin Poirier in December, the winner of that fight will either face Michael Chandler or Justin Gaethje.

Chandler first fought in the U.F.C. in 2020 after a successful run in Bellator M.M.A., considered the second-largest mixed martial arts promotion behind the U.F.C. He won his first fight but lost to Oliveira in the second round via technical knockout in a contest to fill the vacant lightweight title after the dominant champion Khabib Nurmagomedov retired.

Before facing Nurmagomedov in October 2020, Gaethje had a four-fight win streak and won the interim lightweight title.

Both Gaethje and Chandler feature a similar style as capable wrestlers and explosive strikers. This fight starts off the main card, so grab your beer and wings early and don’t blink. This likely won’t last long.