In the first inning, facing St. Louis right-hander Joel Pineiro, the third baseman doubled to left-center field to extend the streak, now the longest in Nationals history.
"I'm trying to get at-bats and not waste any of them. I just stick to my approach throughout the whole game," Zimmerman said.
Nick Johnson advanced to third on the double, but he and Zimmerman were stranded after Adam Dunn and Austin Kearns struck out.
Four innings later, Zimmerman singled and scored on a three-run homer by Dunn.
"He is a good player," Dunn said about Zimmerman. "That's a long time when you can get a hit every game. He is just not an offensive player, he is a real good defensive player as well."
The long streak has made Zimmerman appreciate the dedication Joe DiMaggio had during his record-setting 56-game hitting streak in 1941.
"When you have a 21-game hitting streak, you realize how unbelievable the record and all that stuff is," Zimmerman said. "I really don't worry about that kind of stuff. We are not even halfway there. [DiMaggio's streak] makes me realize how unbelievable that really is."
In his first three full seasons with the Nationals, Zimmerman got off to a slow start each year. But this season is a different story. After Saturday's game, Zimmerman was hitting .306 with five home runs and 16 RBIs.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.