30 years ago, Roger Clemens mowed down 20 Seattle Mariners

The 20-strikeout game is one of baseball's most elusive feats, one that hasn't been accomplished in nearly 15 years.

In fact, over the course of the sport's history, there have only been five such games thrown by major league pitchers, with none more dominant than the gem spun by Roger Clemens 30 years ago. That Tuesday, Clemens became the first to hit the 20-K mark in a nine-inning game, fanning 20 Seattle Mariners hitters in a 3-1 Boston Red Sox win.

Prior to Clemens, baseball's original 20-strikeout effort came in September 1962, when Washington Senators right-hander Tom Cheney sat down 21 Baltimore Orioles hitters in a start. But Cheney's 21 Ks came over 16 innings of work and required 228 pitches. Clemens, meanwhile, did it in 138 pitches in regulation -- with a batter to spare and a little help from Don Baylor, to boot.

Interestingly enough, Clemens wasn't supposed to be pitching on April 29, 1986. Clemens' previous start had come on April 22, and he was scheduled to take the mound on the 27th against the Royals until bad weather in Kansas City washed out the game.

Clemens' start got pushed to the team's next game as a result (one that drew a meager 13,414 fans at Fenway due to a competing Boston Celtics playoff game) and the rest is history.

From the outset, Clemens, then 23 and in his third big-league season, was in control, striking out the side in the first inning. He then struck out two in the second and one in the third before recording his next eight outs via strikeout. During that stretch, Clemens also got an unknowing assist from the Red Sox first baseman Baylor, who dropped a Gorman Thomas popup in foul territory in the fourth.

After the error, Clemens rallied to sit Thomas down looking -- Thomas got his revenge with a seventh-inning homer -- a punchout that later proved to be critical.

"If Baylor hadn't dropped it," Red Sox radio announcer Joe Castiglione told MLB.com in 2011, "he wouldn't have had 20 strikeouts."

Clemens went on to ring up two more Mariners in each of the seventh and eighth innings before starting out the ninth with a strikeout of Spike Owen to put him at 19 for the game. Up next came Phil Bradley, who struck out for the fourth time of the night to put Clemens at the magic number.

The final batter, Mariners first baseman Ken Phelps, also came to the plate with three strikeouts in three at-bats, but he managed a harmless 6-3 groundout to end the game.

"The Ks just kept coming," Clemens told reporters afterward. "But I just wanted to keep it close. I really didn't know I had a chance at it until (Boston pitcher Al Nipper) said I had a chance toward the end. Then the fans were behind me and I knew I had a shot."

Following his 20-strikeout effort, Clemens, who was coming off shoulder surgery, went on to go 24-4 and win the AL Cy Young and MVP awards, as the Red Sox eventually reached the World Series that fall.

Ten years later, Clemens tied his own record with another 20-strikeout game, this time against the Detroit Tigers, and in May 1998, Chicago Cubs rookie Kerry Wood struck out 20 Houston Astros hitters in a win at Wrigley Field. The most recent 20-strikeout start came from Randy Johnson, who fanned 20 Cincinnati Reds batters during the first nine innings of an 11-inning game in May 2001.

In the years since, Ben Sheets and Corey Kluber have come the closest to joining the club, striking out 18 each in May 2004 and May 2015, respectively (Clemens also had an 18-K game of his own in 1998), but no one has matched Clemens' magic mark.

Earlier this season, Vincent Velasquez hurled a 16-strikeout game for the Philadelphia Phillies, and last Saturday Tanner Roark fanned 15 in seven innings for the Washington Nationals, but if history is any guide, it may be a while before we ever see 20 again.

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