A five-week stay for the UFC on Fight Island kicks off in earnest on Saturday with UFC 253 from Yas Island, Abu Dhabi. The main event will feature undefeated middleweight champion Israel Adesanya (19-0) looking to defend his title for the second time against an undefeated challenger in Paulo Costa (13-0).

It is only the second title fight in UFC history that will feature two unblemished records. It will also feature two men who genuinely dislike each other. The fight was supposed to take place earlier this year, but Costa underwent biceps surgery.

It will be Adesanya's first fight since his decision over Yoel Romero on March 7, a fight that was widely panned for a lack of action. Few expect the same result from a fight with Costa, who is an aggressive fighter usually pursuing an early finish.

And because the fight is not in the UFC's Apex facility in Las Vegas, the fights will be held in a bigger cage. Will that help Adesanya, who's generally considered to have better movement and range?

And in the co-main event, the UFC's vacant light heavyweight title is up for grabs between Dominick Reyes (12-1) and Jan Blachowicz (26-8). Former champion Jon Jones dropped the title earlier this year in an anticipated move to heavyweight. Saturday will witness the first 205-pound champion not named Jones or Daniel Cormier since 2011.

The UFC 253 main card starts at 10 p.m. ET on ESPN+ PPV. Marc Raimondi, Brett Okamoto and Jeff Wagenheim recap the fights as they happen on Fight Island.

Conor McGregor wished luck to Israel Adesanya in the #UFC253 main event, which McGregor believes has "fight of the year potential."

(via @TheNotoriousMMA) pic.twitter.com/IWPTaZOHMe

— ESPN MMA (@espnmma) September 26, 2020

Fight in progress:

Men's featherweight: Hakeem Dawodu (11-1-1, 4-1 UFC, +115) vs. Zubaira Tukhugov (19-4-1, 4-1-1 UFC, -135)

Results:

Lightweight: Brad Riddell (9-1, 3-0 UFC) defeats Alex Da Silva (21-3, 1-2 UFC) by unanimous decision

???

— Alex Volkanovski (@alexvolkanovski) September 27, 2020

Recap to come.

Watch this fight on ESPN+.

Welterweight: Jake Matthews (17-4, 10-4 UFC) defeats Diego Sanchez (31-13, 19-13 UFC) by unanimous decision

Matthews caught Sanchez with a straight right hand in the third round, putting Sanchez on rubber legs against the fence. Matthews then pounced, landing hard ground-and-pound until a puddle of blood formed around Sanchez's head on the canvas.

Sanchez, known for being one of the toughest fighters in UFC history, survived the late onslaught. But Matthews was able to take home a one-sided, unanimous-decision (30-26, 30-26, 30-26) win in a welterweight bout.

"I just beat Diego Sanchez. That's pretty surreal."@JakeMatthewsUFC went from watching @DiegoSanchezUFC on TUF to having the honor of facing him at #UFC253 pic.twitter.com/NhBArqyZXS

— ESPN MMA (@espnmma) September 27, 2020

Matthews landed hard shots in each round, including a knee and big right hand in the first and a nice uppercut in the second. It was a lopsided bout, but Sanchez largely avoided a ton of damage until the third round.

"I was 11 years old in my lounge room watching Ultimate Fighter 1 when Diego won," Matthews said. "Now I had the honor of fighting him."

Matthews, still just 26 years old, has now won three straight and six of his past seven. The Australia native debuted in the UFC in 2014, at age 19.

The legendary Sanchez, a 38-year-old New Mexico native, is in the UFC Hall of Fame for his incredible 2009 fight with Clay Guida. "The Nightmare" has lost two of his past three bouts. Sanchez is third in UFC history in terms of cage time (6:37:07), per ESPN Stats & Information research.

-- Raimondi

Men's featherweight: Ludovit Klein (17-2, 1-0 UFC) defeats Shane Young (13-5, 2-2 UFC) via first-round KO

UFC newcomer Ludovit Klein gave the featherweight division something to think about, as he starched Shane Young at 1:16 of the first round in his promotional debut.

Klein (17-2) accepted the fight after Young's original opponent, Nate Landwehr, tested positive for COVID-19. Despite the short notice -- and the fact Klein missed weight during Friday's official weigh-in -- he still closed as a betting favorite over Young. And a little over one minute into the bout, he showed why.

Seriously awesome combo, that! #UFC253

— #OnAmission4Gold (@KelvinGastelum) September 27, 2020

After touching Young (13-5) with the jab, Klein staggered him with a nasty left head kick. Before Young could really even cover up, Klein dropped him with a clean right-hand uppercut. Young went crashing to his back and was immediately saved by the referee, even though he came to rather quickly and ended up grabbing the referee's leg.

For Klein, it's his 16th finish in 17 career wins. It's also the ninth time he has finished an opponent inside the first round.

-- Okamoto

Watch this fight on ESPN+.

Light heavyweight: William Knight (9-1, 1-0 UFC) defeats Aleksa Camur (6-1, 1-1 UFC) by unanimous decision

A little over three weeks ago, Knight was on Dana White's Contender Series fighting his way into the UFC. On Saturday, Knight earned his first UFC win, handing Camur his first career defeat.

Knight was simply too much to handle, powering his way to four takedowns over the last two rounds and keeping Camur in dangerous positions for practically the entirety of those 10 minutes. Knight nearly got a kimura finish at the end of Round 2, but Camur was saved by the horn.

The fight went the distance -- a career first for Knight -- but was an easy call for the judges. Two of them scored all three rounds for Knight, and one judge scored it 29-28.

Knight, a 32-year-old from East Hartford, Connecticut, has won three in a row.

"I actually asked my manager, the second I won, because how fast I won on Contender Series, I was like, yo if you can get me a fight as soon as possible, let me know since I'm close to fight weight," Knight said. "Next thing you know, we land and boom they give me an opponent, and not only that, we're going to Fight Island, I couldn't turn that down."

Camur, who turned 25 on Friday, is from Broadview, Ohio, and is a training partner of heavyweight champion Stipe Miocic.

-- Wagenheim

Watch this fight on ESPN+.

Heavyweight: Juan Espino (11-1, 2-0 UFC) defeats Jeff Hughes (10-4 1 NC, 1-3 1 NC UFC) by first-round submission

Welcome back, Juan Espino.

Gone for nearly two years because of a bad hand injury, Espino returned to the UFC in a big way, stopping Hughes by submission (scarf hold choke) at 3:48 of the first round in a heavyweight bout.

Espino, a talented grappler, looked to take Hughes down right away -- and had plenty of success in doing so. He landed a takedown against the cage, then a big slam. In a scramble, Espino was able to pass to mount and then to side control, where he tied up Hughes' head and arm in a slick choke. The result was read as an arm-triangle, but it was actually a catch-wrestling-style scarf hold.

Espino, 39, won The Ultimate Fighter 28 in November 2018, beating Justin Frazier via first-round submission. The Spain native has won seven straight and has not lost since 2011. Hughes, a 32-year-old Ohio native, is winless in all four of his UFC fights.

"I'm happy. It's been a long time outside of the cage," Espino said. "But every day I never lost motivation. I focused in my training. I'm back.

"I'm a world champion in grappling. It's my first natural move is a submission. All my life I've been grappling, all my life wrestling, it's my instinct. I practice my boxing, I practice my kickboxing, I practice everything, but when I go inside and feel good with my wrestling and grappling, I go."

-- Raimondi

Watch this fight on ESPN+.

Light heavyweight: Danilo Marques (10-2, 1-0 UFC) defeats Khadis Ibragimov (8-4, 0-4 UFC) vs. by unanimous decision

Brazilian light heavyweight Danilo Marques picked up a victory over Khadis Ibragimov in his UFC debut, in a three-round bout that was extremely tedious -- to put it nicely.

Marques, who has trained with the likes of Mauricio "Shogun" Rua and Demian Maia, won the 205-pound contest via judges' scores of 30-27, 29-28 and 29-28, but it was an ugly performance from both at times. Marques appeared fatigued as early as the opening round. Ibragimov, who fell to 0-4 in the UFC, was very inactive on the feet and committed several fouls by grabbing the fence.

Great win for Danilo!! Well deserved #kingsmmma #ufc253

— Marvin Vettori (@MarvinVettori) September 26, 2020

Ultimately, it was Marques' work in the grappling exchanges that won him the fight. He took Ibragimov's back multiple times and threatened to secure a rear-naked choke in the second round. Ibragimov hurt Marques with an overhand right late in the fight and nearly submitted Marques with a guillotine shortly after, but that was about the extent of his offense.

Marques, 34, was initially scheduled to compete on Dana White's Contender Series this summer; however, his bout was canceled and he ended up getting the call for Fight Island.

-- Okamoto

Watch this fight on ESPN+.

Still to come:

Middleweight: Israel Adesanya (c) (19-0, 8-0 UFC, -180) vs. Paulo Costa (13-0, 5-0 UFC, +160)
Light heavyweight: Dominick Reyes (12-1, 6-1 UFC, -270) vs. Jan Blachowicz (26-8, 9-5 UFC, +230)
Men's flyweight: Kai Kara-France (21-8, 4-1 UFC, -230) vs. Brandon Royval (11-4, 1-0 UFC, +190)
Women's bantamweight: Ketlen Vieira (10-1, 4-1 UFC, -185) vs. Sijara Eubanks (7-4, 4-2 UFC, +165)
(c) = defending champion