This is Paxton's biggest weapon

James Paxton has brought the Yankees a rare kind of fastball for a starting pitcher. The combination that sets him apart: He has both high-end velocity and the ability to not just maintain it, but raise it, deep into a game.

Fans in the Bronx got their first good look this week, when Paxton -- who starts at Yankee Stadium again on Sunday in New York's 1:05 p.m. ET homestand finale against the Royals -- introduced himself to the Yankees-Red Sox rivalry by outclassing Chris Sale with eight scoreless innings of 12-strikeout baseball. The four-seamer was at its overpowering best.

Paxton was throwing 97 mph heaters even as he crossed into the eighth inning and over the 100-pitch threshold. He capped his night by pounding in fastballs to Mookie Betts -- 97.3 mph, 97.1 mph, 97.2 mph, 98.5 mph, 97.7 mph, 97.4 mph -- until he got the reigning American League MVP to pop up to short right field on his 110th pitch.

Late-inning explosiveness is Paxton's calling card, putting him in a shrinking class of workhorse power pitchers. And it's exciting to watch a starter firing high-90s fastballs into the seventh, eighth and ninth innings like he can.

"I just find that rhythm that I'm looking for," Paxton said. "I can just let it rip more and more. The more rhythm that I find, the more I have at the end to go get."

Highest avg. 4-seam fastball velocity in the 7th inning or later
Active starting pitchers, since Paxton's debut
1-T) Noah Syndergaard (NYM): 97.8 mph
1-T) Luis Severino (NYY): 97.8 mph
3) Nathan Eovaldi (BOS): 96.7 mph
4) James Paxton (NYY): 96.5 mph
5) Gerrit Cole (HOU): 96.4 mph

But the coolest part isn't just that Paxton throws hard late in the game. It's that, late in the game, his fastball gets faster.

Paxton's career fastball velocity by inning
1st inning: 95.3 mph
2nd inning: 95.6 mph
3rd inning: 95.7 mph
4th inning: 95.8 mph
5th inning: 96.0 mph
6th inning: 96.3 mph
7th inning: 96.3 mph
8th inning: 97.1 mph
9th inning: 97.0 mph

That's a steady trend upward, a velocity increase in nearly every inning. Paxton's velocity jumps by nearly 2 mph from the first inning of a game -- when he sits just above 95 mph for his career -- to the eighth and ninth, when he reaches 97 mph and higher.

"To be able to sustain my power is kind of what I train for," Paxton said. "I train for nine innings."

Paxton's average four-seam fastball velocity is 95.8 mph for his career. But when you break down the game into its beginning, middle and end -- three three-inning segments -- you can see that most of that velocity comes later on.

Paxton's progressive in-game velocity
Career 4-seam velo in each third of game
Innings 1-3: 95.5 mph
Innings 4-6: 96.0 mph
Innings 7-9: 96.5 mph

Since Paxton's career began in 2013, he's one of five MLB starters to average a 95-plus mph fastball while also raising that velocity across each third of the game, from the first three innings to the middle three innings to the final three innings.

Elite in-game velocity gainers, since Paxton's debut
Avg. 4-seam velo of 95+ mph and velo increase in each third of game
James Paxton: 95.5 mph » 96.0 mph » 96.5 mph
Luis Severino: 97.0 mph » 97.3 mph » 97.8 mph
Gerrit Cole: 96.1 mph » 96.3 mph » 96.4 mph
Michael Fulmer: 95.5 mph » 95.7 mph » 96.0 mph
Yordano Ventura: 97.2 mph » 97.3 mph » 97.6 mph

Paxton's ability to reach new gears as the game gets to the end has produced some of his most memorable career moments. His no-hitter against the Blue Jays last May 8 is the best example.

In the first three innings that day, Paxton's four-seamer averaged 94.4 mph. In the middle three innings, it jumped to 95.1 mph. Over the final three innings, it reached 96.8 mph. By the ninth inning, Paxton was throwing his hardest. He averaged a game-high 97.5 mph in the frame. And he finished the no-hitter with three huge fastballs to Josh Donaldson -- 98.3 mph fastball for a swinging strike, 99.5 mph for a called strike and 99.0 mph for the game-ending groundout -- on his 97th, 98th and 99th pitch.

The fastball is the foundation of Paxton's dominance. The four-seamer is his greatest weapon, and its swelling velocity is his four-seamer's greatest quality.

"I guess there's something to be said for knowing you're getting close to the end of the game," Paxton said. "There's something to be said for knowing it's your last inning. You can empty the tank."