25 years ago, Kerry Wood pitched the game of a generation originally appeared on NBC Sports Chicago

In just his fifth career start, there was no indication that history would be on the horizon for Kerry Wood at Wrigley Field on May 6, 1998.

Sure, there were plenty of lofty expectations for the right-handed rookie. Picked fourth overall by the Cubs in the 1995 MLB Draft, Wood was named the fourth-best prospect in baseball prior to the 1998 season by Baseball America.

Making his first four starts in April 1998, the 20-year-old Wood delivered mixed results. While he delivered five shutout innings and seven strikeouts against the Dodgers at Wrigley Field on April 18 and tossed seven innings of one-run ball at home against the Cardinals on April 30, there were plenty of hiccups in Wood's first taste of the big leagues.

In his MLB debut north of the border in Montreal, Wood surrendered four runs and three walks in four and two-thirds innings, while recording seven strikeouts in a 4-1 loss to the Expos.

At Dodger Stadium on April 24, Wood was tagged for seven earned runs and four walks while failing to make it out of the second inning, brightly highlighting the rookie's issues with control as a prospect.

So on a cloudy Wednesday afternoon in early May when the 20-11 Astros were in town against a 16-15 Cubs team, it was that the Cubs and their fans had no idea what to expect, as the rookie was being handed the most significant offensive test of his career to that point.

The Astros were manned by the "Killer B's" lineup in 1998, with Hall of Famers Craig Biggio and Jeff Bagwell comprising the heart of their order alongside power-hitting outfielder Derek Bell.

Supplemented by then-future Cub Moises Alou and an offensively-minded catcher in Brad Ausmus, the Astros lineup was one of the most potent in baseball, and perhaps the most dominant in the National League. 

The Astros' 109 OPS+ as a team led the NL and trailed only the Yankees and Mariners in 1998, with 874 runs also being an NL-best in a season remembered for offensive prowess.

On this cloudy Wednesday afternoon however, a 20-year-old Kerry Wood was having none of that.

On top of facing a dominant Astros lineup, Wood also had to counter then-Astros ace Shane Reynolds, who would go on to deliver an excellent pitching performance of his own, striking out 10 Cubs over eight innings of work.

While there have been 318 no-hitters and 23 perfect games in MLB history, Wood's performance 25 years ago today stands out as a uniquely great effort, even beyond the statistical feat of striking out 20 hitters in a nine-inning game, tying a record twice performed by Roger Clemens at the time.

In nine innings of essentially flawless baseball, Wood fanned 20 Astros while hitting one batter and allowing a Ricky Gutierrez infield single that many Cubs fans insist was a Kevin Orie error.

From the top of the game when Wood encountered Craig Biggio, he quickly established what would help entice hitters all afternoon: tantalizing late movement on his fastballs.

After witnessing Biggio chase a fastball high and outside that looked like a meatball split seconds earlier, Bell looked foolish as he badly missed on an 0-2 curveball that disappeared after crossing the plate.

To strike out the side in the first, Wood returned to his high fastball that got Biggio swinging, except painting the corner and getting a beneficial call this time to freeze Bagwell looking.

It was late fastball movement that got Jack Howell to swing through a pitch to start the second inning, and Moises Alou would not have a fate much different.

After attacking the high, outside corner in earlier plate appearances, Wood got his future teammate to swing through a fastball up and in that would have resulted in a foul ball at best. 

A following flyout from Dave Clark to end the second was the first moment of fair contact in the game for Houston.

After giving up a leadoff single in the 3rd to Ricky Gutierrez, now with a 1-0 lead, there was a brief moment where it looked that the stellar performance thus far could go awry.

Facing a 3-2 count to Brad Ausmus, a fastball just outside the zone got Ausmus to swing through, and that was just about all of the threatening the Astros would do for the afternoon.

Wood converted an out on a Shane Reynolds sacrifice, and following a balk, got Biggio to ground out to end the inning.

After a Derek Bell flyout to lead off the fourth, Wood started to make statues out of his opponents.

Facing another 3-2 count to Jeff Bagwell, the rookie went back to his devastating, disappearing curveball that froze a hitter long-known for excellent strike zone judgment.

Encountering Jack Howell after Bagwell, Wood froze the infielder by painting the outside corner, finishing the fourth with eight strikeouts to his name.

The two called strikeouts were only the beginning of an unbelievable six straight then recorded by Wood, starting by attacking the outside corner on an 0-2 offering to Alou to start the fifth inning.

The 20-year-old then created more magic with his curveball, making Derek Bell a pedestrian on yet another 0-2 pitch. 

On a 2-2 pitch to Ricky Gutierrez, who had the lone Astros hit, Wood once again went to the outside corner and got the call, picking up his sixth called strikeout of the afternoon and 10th total.

After Ausmus grounded out to shortstop to begin the sixth, Wood made routine work of his counterpart in Shane Reynolds, dispatching the pitcher with a called strikeout on an 0-2 fastball.

The Astros then got their second and final baserunner of the game after Wood plunked the all-time hit by pitch leader in Craig Biggio before inducing a Sandy Martinez lineout to end the frame.

Entering the seventh inning with 12 strikeouts, Wood was seemingly unconscious for the rest of the game, striking out eight of the final nine hitters.

He caught a breeze in the seventh inning, getting Bagwell to swing through a high 3-2 fastball before blowing a heater by the bat of Jack Howell for his fourteenth strikeout.

After Moises Alou couldn't check his swing on a 1-2 pitch, Wood entered the penultimate frame with 15 strikeouts, knocking on the door of history against a prolific lineup in just his fifth start.

Wood went on to get both Dave Clark and Ricky Gutierrez swinging to start the eighth inning, making it five straight swinging strikeouts and 17 total for the outing.

With his curveball perplexing Dave Clark for Wood's 16th strikeout, the rookie then set the Cubs' single-game strikeout record.

An 0-2 curveball then caught the lower outside corner, freezing Brad Ausmus to end the inning and sent Wood to the final frame with 18 strikeouts.

A Jose Hernandez RBI groundout added another insurance run for the Cubs in the bottom of the 8th, giving Kerry Wood a two-run lead on the somehow unthinkable chance that his start went off the rails at the end.

Which, of course, there was no way it could have.

Wood then notched perhaps his most foolish-looking strikeout of the game, getting Bill Spiers to swing through a breaking ball that essentially ended up directly behind him, giving Wood seven consecutive strikeouts and 19 total, which tied a National League record.

After Craig Biggio interrupted Wood's improbable strikeout binge by grounding out to shortstop on a 1-0 pitch, the stage was set for one of the most unforgettable moments in franchise history.

Working Derek Bell to a 1-2 count, Wood's 122nd pitch of the game collapsed out of the strike zone moments before Bell swung through the offering, giving Wood his historic 20th strikeout.

Wood's performance in his fifth start remains one of the greatest in baseball history, standing out even among no-hitters and perfect games as a uniquely dominant outing.

Against a prolific offensive lineup that anchored the Astros to a 102-win season in 1998, Wood's best stuff was firing on all cylinders from the first offering to the final pitch. The late movement on his pitches and particular niche for executing put-away pitches made even the most powerful of lineups look as if they were back in Little League.

Wood of course went on to have an illustrious, albeit injury-prone career, the vast majority of which was spent on the North Side, where Wood adjusted as his injuries and surrounding roster led his role to constantly change.

In accordance with the Game Score metric, which was devised by statistician Bill James in 1988 to better evaluate a starting pitcher's performance, Wood's 20-strikeout outing 25 years ago today remains the greatest starting pitcher performance of all-time, notching a Game Score of 105.

Wood went on to win NL Rookie of the Year, playing a vital role in the Cubs making their first postseason appearance since 1989, finishing 13-6 with a 3.40 ERA, striking out 233 hitters in just 166.2 innings.

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