Brian Ortega
Brian Ortega will finally challenge for UFC gold against Max Holloway next month. In this picture, Ortega celebrates his victory over Frankie Edgar following their featherweight bout during UFC 222 at T-Mobile Arena in Las Vegas, Nevada, March 3, 2018. Isaac Brekken/Getty Images

With just under two months left for 2018 to end, it's been a memorable year for the UFC.

Conor McGregor returned for the first time in nearly two years when he took on Khabib Nurmagomedov in the main event of UFC 229 — a pay-per-view which went on to become the biggest ever with a reported 2.4 million buys.

Daniel Cormier became just the second simultaneous two-weight champion after knocking out Stipe Miocic at UFC 226 and has since become the first champion to defend both the light heavyweight and heavyweight titles following his UFC 230 win over Derrick Lewis earlier this month.

Henry Cejudo ended the long flyweight title reign of Demetrious Johnson, while Yair Rodriguez recently delivered what might be the best finish in UFC history when he knocked out Chan Sung Jung with just a second remaining in their UFC Denver main event over the weekend.

Despite all that has happened and what promises to be an even more exciting 2019 given the plans in store, there are still some big fights left in the calendar year. Here are five of them:

Jon Jones vs. Alexander Gustafsson, UFC 232, Dec. 29

Jones will be making yet another return from a suspension due to a failed drug test when he takes on Gustafsson for the vacant light heavyweight title in the main event of UFC 232.

This fight is not only monumental because it is Jones and Gustafsson's first foray into the octagon for more than a year, but it is also a rematch between the pair following their 2013 fight at UFC 165 which many regard as the greatest title fight in history.

Jones would win via unanimous decision that night, although some believe Gustafsson had a solid case for the win as well, and the rematch promises to be even better.

Will Jones have a triumphant return and continue his legacy as the greatest fighter of all time? Or will Gustafsson deliver his first decisive defeat in what could be the Swede's last-ever title shot?

Max Holloway (C) vs. Brian Ortega, UFC 231, Dec. 8

In what is one of the most stylistically-intriguing matchups of the year, Holloway will finally defend his featherweight title against Brian Ortega in the main event of UFC 231.

The duo were initially supposed to fight in the co-main event of UFC 226 before Holloway had to pull out, but the featherweight stars will finally get to collide next month.

Will Holloway continue his tear and make it 13 straight wins by overwhelming Ortega on the feet? Or will the undefeated Ortega end the winning streak and start his own era as champion by taking the fight to the ground?

Given their ages and the fact that these two are the best 145-pounders in the world today, UFC 231 may even be the start of a potential trilogy.

Cris Cyborg vs. Amanda Nunes, UFC 232, Dec. 29

A battle between two hard-hitting Brazilians, Cyborg will defend her women's featherweight title against Nunes in the co-main event of UFC 232.

Both fighters are yet to be relatively tested in their last few fights which makes this contest all the more interesting. Both fighters are each other's biggest tests, probably in their entire careers, and both also have the power to end the fight within an instant.

A win for Cyborg would continue her run as the featherweight queen with seemingly no contender who could challenge her afterward.

Meanwhile, a win for Nunes would make her the first female two-weight champion and likely cement her place as the best female fighter of all time as she boasts wins over the likes of Ronda Rousey, Miesha Tate and Valentina Shevchenko.

Kevin Lee vs. Al Iaquinta, UFC Milwaukee, Dec. 15

One of the most underrated matchups left in the year, Lee will take on Iaquinta in a rematch from their 2014 fight at UFC 169 in the main event of UFC Milwaukee.

Back then, Iaquinta comfortably defeated a debuting Lee via unanimous decision, however, things will not be so straight forward this time around.

Lee has improved considerably as he has established himself as one of the top contenders in the shark tank that is the lightweight division. Iaquinta meanwhile, will be looking to bounce back from his one-sided defeat to Khabib Nurmagomedov earlier in the year.

Both fighters don't like each other and both have a wrestling base, so it should be interesting to see how the contest plays out with the winner likely edging closer to a title shot.

Curtis Blaydes vs. Francis Ngannou, UFC Beijing, Nov. 25

Another rematch takes place later this month as Blaydes takes on Ngannou in the main event of UFC's debut event in Beijing, China.

Ngannou defeated Blaydes via TKO (doctor stoppage) in April 2016 during his frightening run that culminated in him challenging Stipe Miocic for the heavyweight title at UFC 220 in January this year.

However, Ngannou was thoroughly dominated by Miocic who used his wrestling to win a lopsided decision. The Cameroonian is seemingly still carrying the effects of that defeat based on his heavily-criticized decision defeat against Derrick Lewis at UFC 226.

Blaydes meanwhile, is on a four-fight winning streak, and is looking to avenge his only defeat in MMA and put himself next in line for a title shot.

The contest is intriguing because Ngannou will have been affected by the criticism of his Lewis fight and ideally, will be be back to his pre-Miocic self with the help of his coaches. In addition, it will be interesting to see his improved wrestling game in preparation for this fight.

However, if his mental state is still fragile or if he is overwhelmed by the wrestling pedigree of Blaydes, things could go from bad to worse for the fighter whom many predicted to be the next breakout star.