In the fourth inning of the Cardinals' 11-10, 13-inning loss to the Nationals on Thursday night, the slugger obliterated an 0-1 fastball from Jordan Zimmermann, drilling the pitch into the right-center-field seats. The Nationals do not announce estimated distances on home runs, but the ball easily cleared the wall and got several rows deep into the stands.
Washington center fielder Nyjer Morgan appeared to think for a while that he had a bead on the ball, but watched helplessly as it soared into the seats.
The homer started a rally that put the Cardinals ahead, but ultimately St. Louis couldn't hold that or another later lead.
"It did come really early [in the game]," Pujols said. "It's pretty special, obviously. It's a really special milestone that you reach. But I don't play for numbers. My goal as a little boy was to try to do whatever I can to be a professional baseball player, and the Cardinals gave me the opportunity. God allowed me to have the opportunity, which I thank Him for that."
Pujols is the third-youngest player in Major League history to reach the milestone, at 30 years, seven months and 10 days. Only Ken Griffey Jr. and Alex Rodriguez hit 400 at an earlier age. Only four players in the history of the game reached their 400th homer in fewer at-bats than Pujols, who got there in career at-bat No. 5,615.
He's the 47th player in Major League history to reach 400, breaking what had been a three-way tie at 399 with Andres Galarraga and Al Kaline. Pujols is 10th in home runs among active players. Still, the fact that the dinger came in a defeat took some of the luster away from the achievement.
"We'll talk about that tomorrow," manager Tony La Russa said when asked about the milestone. "We got beat, and I'm certain he doesn't want to talk about it. We lost a tough game, so all the individual stuff, you put that in a different pile for discussion tomorrow."
It was Pujols' 34th long ball of the season and his 10th in 21 games this month.
Matthew Leach is a reporter for MLB.com. Read his blog, Obviously, You're Not a Golfer and follow him on Twitter at @MatthewHLeach. This story was not subject to the approval of Major League Baseball or its clubs.