Walker Cooper is the other player. He went 6-for-7 with three home runs and 10 RBIs for the Cincinnati Redsagainst theChicago Cubson July 6,1949.
"I may have had three home runs in high school," Rendon said of his historic game, "but never like that with the RBI."
Rendon is just the fourth player in the modern era (since 1900) to go 6-for-6 and have at least three home runs in a single game, joining Ty Cobb (for the Tigers on May 5, 1925), Edgardo Alfonzo(for the Mets on Aug. 30, 1999) and Shawn Green(for the Dodgers on May 23, 2002). Green hit four home runs in his 6-for-6 game.
Rendon became the 13th player in major league history to drive in 10 or more in a game and the first since Garret Anderson did it for theLos Angeles Angelsin 2007.
The third baseman said he had a small idea of the history he was making.
"I was aware of some of it," Rendon said. "And then[Stephen] Drewcame up to me, and after I hit the double to right-center, I think that made it nine [RBIs]. I think he told me, 'That's a record. I'm glad I was here to watch it.' That's when I knew for sure."
Rendon, who came into Sunday's game with five RBIs on the season, set a Nationals franchise record with his single-game RBI total.
"It was nice to see Anthony get going today," manager Dusty Baker said. "We just have to build on it. We've got a long way to go and hopefully a lot more runs to score."
Rendon's three home runs came off Sean Gilmartin in the third and fourth and catcher Kevin Plawecki in the eighth inning.
Plawecki became the first Mets position player to pitch in a game since another backup catcher, Anthony Recker, did so on June 30, 2013 -- also against the Nationals.
Rendon had nine RBIs by the fifth inning Sunday. According to the Elias Sports Bureau, Rendon was the first player to have nine RBIs by the fifth inning since Alex Rodriguez accomplished the feat for the New York Yankees on April 26, 2005, against the Angels. Rodriguez finished that game with 10 RBIs.
The last National League player to have nine RBIs through five innings was Gil Hodges for the Brooklyn Dodgers against the Boston Braves onAug. 31, 1950.
The Mets had never allowed an opposing batter to have 10 RBIs in a game before Sunday.
The Nationals beat the Mets 23-5, the most runs they have scored in a single game in franchise history.
ESPN Stats & Information contributed to this report.