The 2017 racing season provided some of the most exciting and intense action in recent memory starting with a dominating Round 1 performance at Anaheim in Supercross and ending with a commanding Round 12 performance at the Ironman National in Motocross.

Supercross went down to the wire in the 250 East class and the 450 class - both providing epic finales talked about for months. Riders played hot potato with the Red Plate in Motocross as individual win streaks kept fans guessing all season on the eventual outcome.

Retirements happened, injuries grabbed headlines and lots of firsts too. First time winners in both series as well as Champions. Then, some guy from the Netherlands who competes overseas showed those racing in America how it's done.

Without doubt, dirt bike racing raised the bar this year offering so much style and much substance. Let's take a look at what dominated the headlines and turned 2017 into one of the most memorable years ever for Supercross and Motocross.

1. Ken Roczen's Injury

In the crash heard round the world, Ken Roczen's Supercross season came to an abrupt end as did the entire year. After dominating wins in the first two rounds, Roczen trailed Ryan Dungey in Round 3 before a kicker tossed him off his dirt bike through the air. He broke his arm and dislocated his wrist and elbow. He detailed, sometimes graphically, his recovery on social media all the while maintaining a return to racing. Later it was revealed he suffered a compound fracture and was at risk of losing his arm. After months of rehab, Roczen appears race ready and expects to line up at A1 next week and contend for the 2018 Monster Energy Supercross Championship.

2. Paging Ryan Dungey

After Roczen went down, everyone seemed fit to hand Dungey the 2017 Supercross Championship. Dungey wanted none of that talk and it looked rather premature too as the three-time Champion hardly dominated as most thought and even lost the points lead to Tomac who won nine rounds on the season to Dungey's three. After finishing third at Indianapolis Dungey, to the surprise of many, said, "It's just a dirt bike race. There are bigger things in life."

Something seemed off with Ryan Dungey during Supercross and turns out, something was

But Dungey never placed lower than fourth all year and a few mistakes cost Tomac some big points as Dungey's style of consistency kept him in all the way to the end as well as a little help...

3. Let Dungey By

In the penultimate round at East Rutherford, Tomac carried the Red Plate by three and led early before washing out, losing the lead then later cased a jump. He never recovered in his bid for 10 wins on the season and settled for eighth. After his crash, Dungey got out front but fell behind his teammate and training partner Marvin Musquin, who led the final 13 laps and appeared headed for the checkers. However, a victory for Dungey offered three extra Championship points, a nice cushion heading into Las Vegas. On the final lap, Musquin pulled off giving Dungey the lead, the win and a nine point advantage in his quest for the title. Afterwards, the team admitted no shenanigans as Musquin, who finished second, simply said he made a mistake.

Help or no help, Ryan Dungey celebrates crossing the checkers at East Rutherford which was also his final career win

4. Round 17 of the Supercross Series

In one of the most exciting title chases in Supercross history, the final round went down to the last lap for the 250 East Class Championship and the 450 class Championship. Adam Cianciarulo, who entered 14 points from the lead in fourth-place and a long shot at the 250SX East crown, grabbed the holeshot and checked out. He appeared headed for the improbable Championship thanks to points leader Jordan Smith crashing out, Zach Osborne's crash at the start and a crash by Joey Savatgy. Little did he or Savatgy know, Osborne worked his way towards the front as Savatgy made the necessary gains to get in line for his first title. However, on the final lap with Cianciarulo already at the finish, Osborne dumped Savatgy in a turn and headed for the waving checkers finishing in seventh-place and winning the Championship by two over Cianciarulo.

If that wasn't enough the 450 class redefined the term barn burner as Eli Tomac needed nine points to beat Dungey for the Championship. The two played cat and mouse all evening as Tomac parked Dungey several times in corners hoping for an edge by getting him caught in traffic rather than just straight-up winning and letting the cards fall where they may. The strategy ultimately backfired as the two got hung up on the final lap allowing Jason Anderson by for the win, while Tomac took second and Dungey fourth. Dungey held on to enough points to grab his third straight Supercross Championship and fourth overall. The extra three points he got from winning the prior round perhaps provided some mental security but ultimately were unnecessary.

5. Dungey Says Goodbye

The spot for Dungey's fourth Championship probably wasn't even on the mantle before he called it a career. On May 16, four days before the start of the 2017 Motocross season, Dungey retired. It was hardly a surprise though most expected the announcement after a last hurrah in Motocross. Turns out a crash the previous year in Motocross resulting in a broken neck began a long spiral for Dungey's enthusiasm to race and Roczen's devastating crash didn't help. Lots of answers finally came out and the whole "What's Wrong with Dungey" earlier in the season proved correct. Something was wrong - his heart just wasn't in it anymore.

Ryan Dungey retired on top in 2017

6. Red Plate Changes in Motocross

With Dungey out, everyone seemed fit to hand Tomac the 2017 Motocross Championship. He thoroughly dominated two years earlier before a crash ended his season and his victories in the prior months for Supercross proved relentless. He powered out the gate in Round 1 taking both Motos and whispers of the undefeated season that got away two years prior grew louder. Then Musquin happened. And Blake Baggett.

Marvin Musquin was one of three points leaders in Motocross

Tomac lost the lead to Musquin in Round 2, who lost the lead to Baggett in Round 4 before handing it back to Tomac in Round 6. Meanwhile, Anderson hung around in third making it a four-rider Championship race before a practice crash ended his season. Eventually, along with a Musquin's torn meniscus and Baggett's thumb injury, Tomac figured out it out and once he took the Red Plate back he kept it for good.

7. Zach Osborne wins two Championships

The reborn and rejuvenated Zach Osborne at 27 years old, who at one time left the United States to try his luck racing overseas, won four of nine 250SX East rounds to clinch his first career Supercross Championship and dominated the 250 class in Motocross for his first career Outdoor Championship. Just a year prior, he landed his first Motocross win and grabbed his first Supercross victory this year en route to the title.

Zach Osborne celebrates his 250SX East Championship and a few months later celebrated the 250 class Motocross Championship

8. Jeffrey Herlings Sweeps Ironman

One of the biggest stars in the World Motocross Championships (MSXP) entered the final round of the American Outdoor series and thoroughly dominated. Jeffrey Herlings, a three-time MX2 (250) class Championship and at-the-time in second for points in the MXGP (450) class, was stateside for racing an MXGP round the following week in Florida. He didn't grab holeshots but led all 16 laps in Moto 1 as Tomac gave chase before crashing. Herlings crashed in Moto 2 but won anyway, climbing from last to overtake Musquin for the lead, the win and overall.

9. Eli Tomac Wins 2017 Motocross Championship

Tomac secured his first 450 class Motocross Championship but it didn't come easy. After sweeping Hangtown he lost the points lead and didn't get it back until five rounds later after sweeping Red Bud. He never relinquished thereafter but Musquin, who damaged his knee prior to High Point, recovered - albeit a bit late - and strung off six straight Moto wins to make it interesting. Tomac needed just 22 total points in the final round, almost threw it away after crashing while chasing Herlings, but dialed it back, finished sixth overall and took home the trophy by 17 points.

Eli Tomac made it interesting but clinched the 450 class Motocross Championship in the final round

10. Musquin wins MEC and more

Musquin the would-be heir apparent to Dungey on the Red Bull KTM team seems ready for the challenge as he swept the Monster Cup becoming the second rider in history to claim the $1 million prize and won Red Bull Straight Rhythm, both in October, then he went overseas and started winning off-season races there. He challenged Tomac to the end in Motocross and enters the 2018 season as a heavy favorite.