For 51 years, Hall of Famer Tom Seaver held what increasingly looked to be one of baseball's more untouchable records: 10 consecutive strikeouts within one game.

But as strikeout rates soar across the Major Leagues, that mark is now getting challenged often. In fact, Seaver now shares the top of that mantle with Brewers ace Corbin Burnes -- who accomplished the feat Aug. 11, 2021, against the Cubs -- and Phillies hurler Aaron Nola, who in June that same year became the first to finally tie Tom Terrific with 10 straight K's against Seaver's former team, the Mets.

Another Mets ace, Jacob deGrom, seriously challenged the record with nine straight K's in April 2021, and Marlins righty Pablo López did the same in July. And on Monday night, Rangers right-hander Andrew Heaney struck out nine straight Royals.

The hot streaks of Burnes, Nola, deGrom, López and Heaney have now increased the list of pitchers with at least nine straight K's in an AL or NL game to 13. Here's a rundown of those performances.

10 -- Corbin Burnes (MIL)
Aug. 11, 2021, at Cubs

Burnes was absolutely dominant from the start, needing just four pitches to get through his first inning of work. But the best was yet to come.

Starting with Frank Schwindel to lead off the second inning, Burnes mowed down 10 consecutive Cubs batters on just 50 total pitches. A single by Matt Duffy ended Burnes' chance to secure the top spot on the leaderboard for himself, but the Brewers ace bounced back to strike out Greg Deichmann for his 11th consecutive out via strikeout. Thanks to a David Bote lineout which ended the game's fifth frame, Randy Johnson remains the record holder in that regard with 13 straight outs via punchout.

10 -- Aaron Nola (PHI)
June 25, 2021, vs. Mets

Nola's afternoon got off to a somewhat shaky start with a hit by pitch followed by a Francisco Lindor double, but it's safe to say he locked in after that. Nola proceeded to pick up each of his first 10 outs of the ballgame via strikeout, adding some poetic asymmetry with Seaver's record-setting game, when Seaver notched each of his last 10 outs via the K. The hapless Mets hitters had a patch featuring Seaver's No. 41 on the shoulder of their uniforms to honor the late Hall of Famer following his passing the previous year.

After Pete Alonso finally snapped Nola's streak with a double, the Phillies ace notched one more punchout to end the inning -- giving him a scorching 11 through the ballgame's first four innings.

10 -- Tom Seaver (NYM)
April 22, 1970, vs. Padres

The Mets led the Padres 2-1 behind an already strong outing from Seaver in the top of the sixth, when the righty struck out Al Ferrara to end the inning. Seaver would go on to complete the game and he recorded each of the final 10 outs via strikeout beginning with Ferrara. Seaver finished the game with another strikeout of Ferrara to seal the Mets' 2-1 win. It was Seaver’s 19th strikeout overall, marking his career best. At the time, he was the first pitcher to strike out 19 batters in a nine-inning outing, though four pitchers have since racked up 20.

9 -- Andrew Heaney (TEX)
April 10, 2023, vs. Royals

Beginning with Matt Duffy in the top of the first inning at Globe Life Field, Heaney struck out all nine hitters in Kansas City's starting lineup in succession -- eight of them swinging. The streak ended when Duffy came back to the plate in the fourth and flied out to right field. Overall, Heaney struck out 10 and walked two over five innings, giving up an unearned run on two hits. Incidentally, Heaney's career high of 14 strikeouts also came in Arlington when he pitched against the Rangers while with the Angels at the current park's predecessor, Globe Life Park, on Aug. 20, 2019 (Game 1 of a doubleheader).

9 -- Pablo López (MIA)
July 11, 2021, vs. Braves

López climbed the mound for the Marlins' last game before the 2021 All-Star break and decided to make a whole bunch of history. The right-hander struck out each of the first nine Braves hitters he faced to begin the afternoon, breaking the Modern Era record of eight consecutive strikeouts to begin a game previously held by Jim Deshaies (1986), Jacob deGrom (2014) and Germán Márquez ('18). López needed only 35 pitches to rack up his nine punchouts, which tied Ricky Nolasco (also against the Braves) for the longest strikeout stretch by a Marlins pitcher within any point in a game. After rolling through his first time through the Braves' order, López didn't record a single strikeout across the other 16 batters he faced. Go figure!

9 -- Jacob deGrom (NYM)
April 17, 2021, vs. Rockies

While deGrom didn't quite reach fellow Met Tom Seaver's Major League record, he did come close. After a perfect first, he allowed two batters to reach in the second inning, at which point deGrom struck out nine straight, beginning with Josh Fuentes and working through the Rockies' order. His streak would ultimately end when Fuentes reached on an error to start the fifth, but deGrom wrapped up his outing with four more strikeouts -- two in the fifth and two in the sixth -- matching his career high of 14 in six innings, his shortest outing with 12 or more strikeouts to date.

9 -- Tyler Alexander (DET)
Aug. 2, 2020, vs. Reds

The Tigers and Reds were already set to join the record book when they met on Aug. 2 for a pair of seven-inning games -- the first MLB doubleheader in the Modern Era (since 1900) in which both games were scheduled for fewer than 9 innings. But Alexander’s outing in relief added another layer, as he entered in the top of the third and proceeded to strike out the first nine batters he faced, beginning with Mike Moustakas and ending when he hit Moustakas with a pitch. Alexander tied Doug Fister’s mark for the longest such streak in AL history, and came just one shy of Seaver's record. Alexander’s nine consecutive strikeouts are also a record for a reliever.

9 -- Max Scherzer (WSH)
Oct. 3, 2015, at Mets

Scherzer didn’t only strike out nine in a row in this game, he threw a no-hitter (his second of the season) while racking up 17 strikeouts overall. The Nationals led, 1-0, in the bottom of the sixth when he struck out Curtis Granderson swinging to the end the inning. In the seventh, he got Ruben Tejada, Michael Conforto and Michael Cuddyer, all swinging as well. Then in the eighth, it was Kelly Johnson, Kirk Nieuwenhuis and Kevin Plawecki -- all swinging, again. He struck out Yoenis Céspedes and Lucas Duda to start the ninth, and got to two strikes on Granderson with a chance to tie Seaver’s record in the Mets’ home park before Granderson hit a pop fly to end the game.

9 -- Doug Fister (DET)
Sept. 27, 2012, vs. Royals

The Tigers held a 4-0 lead when Fister took the mound to begin the top of the fourth, and he notched a pair of groundouts before striking out catcher Salvador Perez to close the frame. His strikeout streak kept going until Perez came up to the plate in the seventh and grounded out to the shortstop on a 1-2 pitch. Still, the run was good enough to give Fister the AL record.

"I said, 'Congratulations, man. You made history,’” Tigers teammate Prince Fielder said after the game. “He was like, 'What are you doing?' He was locked in so it was kind of like, 'Get away from me.' I was like, 'All right … they'll tell you.'”

9 -- Aaron Harang (LAD)
April 13, 2012, vs. Padres

Harang’s night began with a leadoff single by San Diego’s Cameron Maybin, but did he ever lock in after that. The next nine Padres walked right back to the dugout until Will Venable snapped the strikeout streak with a homer to lead off the fourth inning. Harang finished the night with 13 strikeouts, but he also allowed four runs over 6 1/3 innings, and the Dodgers needed a walk-off walk by Andre Ethier to pull out a wild 9-8 win in L.A.

9 -- Ricky Nolasco (FLA)
Sept. 30, 2009, at Braves

This was part of a franchise-record 16-strikeout day for Nolasco, who is also the only pitcher to record 1,000 strikeouts in a Marlins uniform. It was Florida’s 159th game of the season and the club had just recently been eliminated from contention for the NL East title, but Nolasco still brought his best, striking out the side in the third, fourth and fifth innings before Adam LaRoche led off the sixth with a double.

9 -- Jake Peavy (SD)
April 25, 2007, at D-backs

Peavy’s big night came in a 16-strikeout performance for the Padres, which tied his own franchise record that he had set against the Braves one year earlier. Peavy struck out the Arizona side in the second, third and fourth innings, relenting only when he walked Eric Byrnes to begin the fifth. It was part of a dominant 2007 season for Peavy, who won the NL’s pitching Triple Crown by pacing the league in wins (19), strikeouts (240) and ERA (2.54) en route to a winning the NL Cy Young Award in unanimous fashion.

9 -- Mickey Welch (NYG)
Aug. 28, 1884, vs. Blues

Welch set a standard that went untouched until Seaver’s outing in 1970. He began this game against the Cleveland Blues by striking out each of the first nine batters. The ninth batter did reach on a passed ball, and as a result, this record wasn’t recognized across the board until the 1940s. Welch totaled 14 strikeouts on the day.