Now that the 2021 season is over, let's look back at the nastiest pitches of the year -- with help from Statcast.

Statcast's tracking technology lets us see the numbers behind the best pitches in baseball, whether it's a triple-digit fastball or a high-spin curveball or a slider with two feet of break.

Here are 15 of the nastiest pitches of 2021.

Aroldis Chapman vs. Matt Chapman, June 19
103.4 mph fastball

The Yankees' closer had his ups and downs in 2021, but this was an up -- the fastest pitch of the MLB season. And it just so happened to be a game-ending strikeout with the tying runs on base. The Yankee Stadium crowd appreciated Chapman dialing up the velocity, that's for sure.

Jacob deGrom vs. Fernando Tatis Jr., June 11
94.9 mph slider

The average Major League fastball is 93.5 mph. deGrom is out there throwing sliders a mile-and-a-half per hour harder than that. This one by deGrom against the NL MVP candidate Tatis was the fastest strikeout by a starter this year on a pitch that wasn't a fastball.

Shohei Ohtani vs. Luis Robert, April 4
92.6 mph splitter

Ohtani's splitter might be the most unhittable pitch in baseball. Hitters went 11-for-127 against it this season, an .087 batting average, with 77 strikeouts. Ohtani dialed this one up to close to 93 mph -- in the same historic start during which he threw 100 mph on the mound and hit a 115 mph homer at the plate.

Dustin May vs. Trent Grisham, April 25
3,539 rpm curveball

The elite threshold for curveball spin is 3,000 rpm. This is way above that. May broke off this backdoor curve for the second-highest-spin curveball K of 2021, the highest by a starter and the highest for a strikeout looking. Nothing's prettier than a curveball that freezes a hitter completely.

Gerrit Cole vs. Xander Bogaerts, July 23
101.3 mph / 2,575 rpm fastball

Not a lot of pitchers can paint the black with a 101 mph fastball. This high-spin, rising fastball from Cole carried right onto the corner of the strike zone, where Bogaerts could only watch it and walk back to the dugout. Cole, deGrom and Sandy Alcantara were the only starting pitchers with a 101 mph strikeout this season, and this one by Cole was the fastest called Strike 3.

Kyle Crick vs. Matt Adams, May 30
Slider with 24.0 inches of break

Here's a literal back-foot slider. Crick's slider broke two full feet from right to left … which is why Adams swung at it even though it was so far inside it ended up hitting him on the back leg. That's a dead-ball strikeout -- one of six slider K's Crick had this season with two-plus feet of break, easily the most of any pitcher. His slider averaged 21.5 inches of horizontal movement in 2021, topping the MLB leaderboard.

Devin Williams vs. Juan Soto, May 29
2,820 rpm changeup / 21.6 inches of break

Williams' unique "airbender" changeup moves like a screwball. Its high spin rate is extremely abnormal for a changeup, which is typically the lowest-spin pitch type -- Williams averaged 2,818 rpm this season; the next-closest pitcher was Trevor Richards at 2,471 rpm, and the MLB average was 1,750 rpm. This one broke almost two feet away from Soto, which is how you so badly fool the most disciplined hitter in baseball.

Charlie Morton vs. Josh Rojas, Sept. 23
3,058 rpm curveball / 13.2 inches of break

Morton's curveball has elite spin and elite movement, and this one was so nasty it got Rojas to swing even though the pitch nearly hit him as it broke over a foot inside. Morton's curveball break was top-10 in the Majors this year.

Justin Lawrence vs. Eduardo Escobar, April 29
101.2 mph sinker / 19.2 inches of break

This amount of movement at this velocity is insane. Over 100 mph and breaking over a foot and a half. In fact, no strikeout pitch this season with triple-digit velocity had more horizontal movement than this one by Lawrence.

Emmanuel Clase vs. Andy Ibáñez, Aug. 26
101.8 mph cutter

Clase throws the hardest cutter on record, and this one is the single fastest cutter strikeout on record -- a 101.8 mph game-ending K. Pitch tracking goes back to 2008, and Clase has all of the 19 fastest strikeouts on cutters in that span. He averaged 100.2 mph with his cutter in 2021. Before Clase, the pitchers with the next-highest cutter velocity in a single season were Garrett Richards (2014) and Kevin Jepsen (2009) … at 96.6 mph.

Tyler Rogers vs. Trea Turner, July 11
Slider with 1.03 foot vertical release point

Rogers has the most extreme delivery of any pitcher in baseball. The submariner releases the ball, on average, just 1.20 feet off the ground -- the next-closest pitcher, Adam Cimber, has a release point a foot higher than Rogers'. This slider started off barely a foot off the ground, and it ended up more than three-and-a-half feet high at the top of the strike zone, making it a true rising slider.

Tyler Glasnow vs. Josh Harrison, June 8
84.5 mph / 2,862 rpm curveball with 7.7 feet of extension

Glasnow's electric stuff looks even nastier to a hitter because of how close to the plate he releases the ball. He's always at the top of the extension leaderboards. Glasnow is a master at getting hitters to chase a power curveball that he spikes into the dirt -- they can't lay off because they have a shorter distance to react. He released this high-speed, high-spin curve nearly eight feet in front of the rubber, resulting in the curveball K with the most extension in 2021.

Zack Greinke vs. Renato Núñez, April 12
51.5 mph slow curve

On the opposite end of the spectrum from Glasnow's power curveball is Greinke's eephus curve, one of the most fun pitches to watch. Greinke will float in his slow curve in the 60s … or even the 50s. Like this one, which was barely over 50 mph and froze Núñez for a called strike -- the slowest strike thrown in 2021 by someone who wasn't a position player pitching.

Corbin Burnes vs. Javier Báez, April 14
98.0 mph / 2,957 rpm cutter

Burnes' nasty cutter fueled his breakout into a Cy Young Award finalist. He struck out 117 batters with it this year, making him the only pitcher since 2008 with 100-plus cutter K's in a season. Burnes throws his cutter at high velocity with lots of spin, and the product is what you see here -- an upper-90s pitch that takes a sharp left turn onto the corner of the plate for a called Strike 3. You can't hit that. You can't even try.

Clayton Kershaw vs. Willson Contreras, June 27
Curveball with 64.8 inches of drop / 1.2 inches of break

Let's end this list of nastiest pitches with one of the most famous of them all: Kershaw's curveball. It's still as beautiful as ever, a true 12-6 curve that continues to freeze hitter after hitter. This one from the Dodgers' longtime ace dropped well over five feet, all while barely moving an inch from side to side, and it splashed right into the strike zone for the backwards K. It was part of a 13-strikeout game for Kershaw.