UFC 249 LIVE: Follow the action with RT Sport's rolling updates as the UFC returns to action in Jacksonville (VIDEO)

AND NEW!

Justin Gaethje just produced the best performance of his MMA career to stop Tony Ferguson after five largely dominant rounds in the main event.

Ferguson's unorthodox approach may have proved tricky against a previous version of Gaethje, but this new-look version looked outstanding. 

Gone was the gung-ho approach, replaced by a considered, cerebral approach that saw him stop Ferguson after five brilliant rounds to capture the interim UFC lightweight title.

TONY FERGUSON VS. JUSTIN GAETHJE

It's time for our main event, and what a fight this could turn out to be.

Tony Ferguson is riding a 12-fight win streak, the longest run in the lightweight division, shared with Khabib Nurmagomedov. 

Gaethje is the most exciting lightweight fighter on the planet.

This should deliver fireworks. Here's our preview:

"TRIPLE C" WINS, THEN RETIRES!

Henry Cejudo put on a superb performance to stop Dominick Cruz with two seconds remaining in the first round of their bantamweight title fight, then surprised everyone by announcing his RETIREMENT from the sport.

"I'm retiring tonight," he told commentator Joe Rogan.

"I'm 33 years old, I'm happy with my career. Uncle Dana, I want say thank you for everything, you're the man. Everybody here, thank you so much. Triple C's out, you guys don't have to hear my ass no more."

HENRY CEJUDO VS. DOMINICK CRUZ

It's time for our first title fight of the night as UFC bantamweight champ Henry Cejudo puts his 135-pound title on the line against former two-time champion Dominick Cruz, who is coming back after three and a half years away from the cage.

BOOM! GONE IN 20 SECONDS!

Francis Ngannou allowed Jairzinho Rozenstruik to land one leg kick, then decided enough was enough and he let fly with a vicious salvo of hooks that left Rozenstruik sat down against the fence, totally unconscious.

That was scary, scary stuff, and it took just 20 seconds.

FRANCIS NGANNOU VS. JAIRZINHO ROZENSTRUIK

The two heaviest hitters in the UFC heavyweight division are about to throw down inside the octagon in our final non-title fight of the night at UFC 249.

Undefeated Jairzinho Rozenstruik has been wrecking UFC heavyweights since his arrival in the promotion, but now he faces the toughest test of his career against a fired-up and powerful Francis Ngannou, who has the hardest recorded punch in history.

It's a fight that will surely end up with someone getting knocked out, but who'll be celebrating and who'll be waking up staring at the arena lights?

Here's our preview:

After Jeremy Stephens started out in typically aggressive fashion, Calvin Kattar started to warm up his hands and, after putting together some impressive boxing combinations, stepped in with a MASSIVE elbow to the chin that sent Stephens crashing to the canvas. 

A few additional strikes, including a nasty elbow, sealed the win for Kattar, who left Stephens with an ugly gash on his forehead.

JEREMY STEPHENS VS. CALVIN KATTAR

Featherweights will fly in our next matchup, as 145-pound wreckers Jeremy Stephens and Calvin Kattar go head to head looking to catapult themselves towards a top contender fight later this year.

Here's our fight preview:

Yorgan De Castro started the better, but Greg Hardy came back strongly to win all three rounds on all three scorecards to claim the win and hand De Castro the first loss of his career.

De Castro looked good early on as he connected with some punishing leg kicks and followed up with some heavy punches. But Hardy weathered the early storm to outwork the Cape Verde heavyweight to earn scores of 30-27 on all three scorecards.

After the fight, Hardy revealed that he heard former two-division UFC champion Daniel Cormier's commentary about Hardy not checking De Castro's leg kicks, and acted on those words by checking kicks from that moment on. It proved to be useful, if unintentional, advice.