The latest work from our old friend and baseball infographic expert Craig Robinson delves into the exclusive 20-strikeout, complete-game club, of which there are just three instances comprised of two members. (Sorry, Randy Johnson.) Looking at Robinson's visual interpretation of all three games, as well as doing a little research, it's clear that Wood's was the more impressive feat.
Bottom line: Wood had eight swinging strike threes—as many as Clemens did in 1986—and punched out eight of the last nine batters he faced. Wood threw a one-hit shutout, allowing just two baserunners. In his first 20-strikeout game, Clemens allowed a home run to the Mariners' Gorman Thomas and struck out six of the final nine. Ten years later in 1996, Clemens gave up five hits to the Tigers and needed 151 pitches to close out the game. (Wood only needed 122 pitches.)
Perhaps the best coda to this debate is that Wood, despite numerous injuries in the 14 years since, is still pitching. He's logged more than 1,300 big-league innings and still has the highest career K/9 of any active pitcher, just ahead of Tim Lincecum. Clemens, meanwhile, isn't doing quite as well these days.