After a year of interesting action that included an MMA star stepping into the boxing ring, here's a look at some of the highlights along with a prediction for 2018.

Fighter of the Year: Demetrious Johnson

A lot of fighters had banner years in 2017 and there are a lot of solid resumes and claims to the title of “Fighter of the Year.”

Max Holloway unified the featherweight strap and defeated the division’s GOAT twice. Robert Whittaker fought two of the toughest middleweights on the planet, Ronaldo "Jacare" Souza and Yoel Romero, winning the interim title and eventually being promoted to champion.

Ryan Bader went 2-0 in Bellator MMA, including winning the light heavyweight title. Volkan Oezdemir went from UFC debut to light heavyweight title shot at UFC 220 in January 2018 in one year with a four-fight win streak. Paul Felder had three wins, all via finish and never saw a third round.

But this year’s fighter of the year is flyweight champion Demetrious Johnson.

Johnson successfully defend his title twice this year, both via the armbar and both earning him “Performance of the Night” bonuses.

Demetrious Johnson, UFC's top pound-for-pound fighter, talks about life, his job and more

When he defeated Wilson Reis at UFC on Fox in April, Johnson tied Anderson Silva’s record for consecutive title defenses. At UFC 216 in December, Johnson broke the record and in stunning fashion.

While the stigma of a cleared out division and lesser opponents unfairly looms over Johnson’s title reign, he dominated opponents and shocked MMA fans around the world with a never before seen belly-to-back suplex with a mid-air transition into the armbar submission.

With the record locked up, Johnson is out to defend his title in 2018 and perhaps add to his legacy with a super fight against bantamweight champion T.J. Dillashaw.

Honorable Mention

Robert Whittaker – 2-0 over top middleweights and won the interim real middleweight title. Argument against: Michael Bisping and Georges St-Pierre casting a large shadow.

Volkan Oezdemir – 3-0, went from non-UFC fighter to light heavyweight title shot in 12 months. Argument against: Shallow division.

Max Holloway – 2-0, unifying featherweight title against Jose Aldo in Brazil and winning the rematch. Argument against: Same fighter twice, and Aldo is now 1-3 in his last four fights.

Brandon Magnus/Zuffa LLC/Zuffa LLC via Getty Images

Fight of the Year

Picking the “Fight of the Year” is a lot like picking the best beer. Some people prefer domestic, some prefer imports. Some prefer IPAs, other people despise IPAs.

Likewise, people are entertained by fights for different reasons. Some people prefer the fighters just letting leather fly with reckless abandon. Some people appreciate technical fights with solid strategy and game planning, appreciate grappling, and some fans don’t find those versions of MMA boring.

But the fight between Michael Johnson and Justin Gaethje was the best of the year.

Gaethje was making his UFC debut after a long, successful career in World Series of Fighting. The question that always loomed over Gaethje’s career was how would he compete against the best and in his UFC debut he got a top-lightweight contender in the main event of a card during International Fight Week.

It also had a lot of build up, from the “Summer Kickoff” press conference at UFC 211 in Dallas, to the clips of trash talk in hotel hallways the spotlight was on.

Gaethje’s fight against Eddie Alvarez at UFC 218 was a contender for this honor, but the fight against Johnson was a back-and-forth war, each fighter willing to go out on his shield. At one point, Johnson dropped Gaethje and it looked like Gaethje’s debut was going to be spoiled.

Gaethje rallied to get the win in remarkable fashion, winning a “Performance of the Night” and “Fight of the Night” bonus.

Honorable Mention

Dustin Poirier vs. Jim Miller, UFC 208 – An incredibly tough, back-and-forth fight.

Eddie Alvarez vs. Justin Gaethje, UFC 218 – Fans were promised violence and the fight delivered. Incredible knee to end the fight.

Yancy Medeiros vs Alex Oliveira, UFC 218 – Back-and-forth fight, each fighter dropping their opponent.

[youtube:https://www.youtube.com/watch?v=PTM7WlfmsQg]

Upset of the Year: Rose Namajunas over Joanna Jedrzejczyk

Headed into UFC 217, the biggest underdog on the card was Rose Namajunas, who was set to challenge Joanna Jedrzejczyk for the 115-pound strap. In hindsight it was absurd. Namajunas fought Carla Esparza for the inaugural strawweight title, her most recent loss was against Karolina Kowalkiewicz, a fight which earned her a shot at Jedrzejczyk.

But the biggest underdog on the card she was, partly because of Jedrzejczyk’s dominance. Jedrzejczyk was on the cusp of tying Ronda Rousey’s record for title defenses and looked dominant in most of her fights. She had won six out of seven title fights in the division’s history.

And Namajunas needed just over three minutes to stop history, in impressive fashion to boot. Namajunas didn’t get a close or controversial decision win, she dropped Jedrzejczyk, one of the best striker’s in women’s MMA, twice.

She overcame the pressure, she overcame the trash talk from Jedrzejczyk and won the title in emphatic fashion on the biggest stage possible in Madison Square Garden.

Is it the biggest upset in UFC history? Perhaps not. History will judge the upset when Namajunas finishes her career, and that title depends on where Namajunas goes from here.

But, the biggest upset of 2017? Definitely, and it came on a night when three champions were upset.

Honorable Mention

Nicco Montaño – Was the 14th seed on The Ultimate Fighter: A New World Champion and won the show and the inaugural women’s flyweight title.

Darren Till vs. Donald Cerrone – Till was a young fighter making his debut against a veteran of the sport in the main event and got a big win.

Georges St-Pierre – Came back after a four-year layoff, moved up in weight and defeated Michael Bisping for the middleweight title, though technically he was the favorite according to the odds.

Rookie of the Year: Cynthia Calvillo

Cynthia Calvillo is 4-0 in 2017, including 3-0 in the UFC. Calvillo made her debut at UFC 209 on 10 days notice against Amanda Bobby Cooper and got a first-round win via a rear-naked choke.

In her second UFC fight, Calvillo was given a pay-per-view slot right before the co-main event and defeated Pearl Gonzalez in the third round with another rear-naked choke.

Then, Calvillo went overseas and defeated Joanne Calderwood in her home country.

Calvillo still has one fight left, against former strawweight champion Carla Esparza at UFC 219, and a win would really put an exclamation point on a tremendous rookie campaign in the UFC, and perhaps cement a claim to “Fighter of the Year.”

Honorable Mention

Volkan Oezdemir – 4-0 in the UFC and earned a light heavyweight title shot against Daniel Cormier.

Nicco Montaño – Wasn’t considered a contender for the women’s flyweight title on The Ultimate Fighter. Knocked off the second, third and sixth ranked fighter on the show. Then beat the No. 1 overall seed, veteran Roxanne Modafferi, to win the inaugural belt.

Paulo Costa – 3-0, including a win over former welterweight champion Johny Hendricks.

Bold Prediction for 2018

Conor McGregor doesn’t defend the belt

There is a lot of talk about McGregor’s future in combat sports. Does he stay in boxing? There are reports Manny Pacquiao is interested in a boxing bout. Does he retire? Dana White thinks with a loaded bank account he might lack the motivation to get punched in the face anymore.

And more importantly does he return to the UFC at all?

McGregor has always been drawn to the next challenge and the most marketable fights, and is proven he isn’t keen to defend belts. Unlike the typical thought process—you’re not a real champion till you defend the belt—McGregor seems to see it as a mountain summitted and looks for the next precipice to tackle.

If he does return to the UFC, could it be for a super fight with Georges St-Pierre? Does he challenge for the welterweight strap? Does he drop back to 145 pounds to win his first UFC title back, a belt he never lost?

All those scenarios have McGregor returning and not defending the belt.

Conor McGregor fans ranked best of year in Sports Figures

Every year, FanSided ranks the best fandoms in the world in a ranking called Fandom 250. Not only does it include sports franchises and athletes, it includes movies, TV shows, celebrities, musicians and brands.

And UFC lightweight champion Conor McGregor finished fifth overall, first in the sports figure category. That’s ahead of Cristiano Ronaldo, Beyoncé, Taylor Swift, the Chicago Cubs, the Dallas Cowboys and the New York Yankees.

The UFC came in at 48th on the list.

It’s hard to contest. McGregor’s popularity has brought an influx of new fans into mixed martial arts, and the UFC. Despite not fighting in the UFC, he still looms large over the company as a whole drawing comments from fighters in all divisions and ire from those in at least two.

But the large reason for McGregor’s prominence in the rankings was the Floyd Mayweather fight. The undefeated boxer acknowledged fan demand as a reason he unretired to take the crossover fight. McGregor’s social media presence exploded, gaining over 10 million followers on Instagram alone.

Mayweather vs. McGregor was the third most searched sporting event in the world according to Google data, behind only Wimbledon and the Super Bowl. The fight was the sixth biggest search in the United States, ahead of the solar eclipse and Hurricane Harvey. How to watch the fight was the fourth most searched in the “How to…” category.