Even more amazing is that most of the victories have come without their franchise player, third baseman Ryan Zimmerman, who hasn't started in more than 10 games because of hamstring problems.
"It's a nice stepping stone," manager Jim Riggleman said about the winning month. "We are trying to win each ballgame. Our guys have really stayed focused each day, no matter what's going on.
"Our guys are focused and trying to play today's game, not thinking about yesterday or tomorrow or down the road. They are just trying to win the game. Hopefully, it will add up and we win another one."
The main reason for the winning record in April is the starting pitching. Take Atilano -- he lasted six innings and gave up two runs on six hits. It marked the seventh straight game in a which a Nats pitcher had a quality outing.
"I'm excited again," Atilano said. "The same thing happened [just like on Friday]. I can't ask for anything better. It was a tough day. I had to battle through the innings. But I feel happy about it."
Atilano showed that he could get out of tough jams in a big way. In the fifth, Chicago had the bases loaded with one out, but Marlon Byrd popped up to first baseman Adam Dunn, and Mike Fontenot hit a ground ball to Dunn, who threw to Atilano for the third out of the inning.
Atilano then showed his emotions, pumping his fist after getting out of the jam.
"I had to be happy on that one," Atilano said. "The bases were loaded. We were up by one at the moment. They had a chance to go ahead or tie the ballgame, so you have to be pumped up."
Riggleman was impressed how Atilano kept his composure.
"He battled and continued to make pitches. He didn't give in to hitters," Riggleman said. "He did a very nice job. Sometimes you are not going to have your best stuff. You still have to compete and win a ballgame."
Atilano, who won his second game of the season in as many starts, was given early run support. With Cubs right-hander Ryan Dempster on the mound, Adam Kennedy hit a solo homer to give Washington a 1-0 lead in the first.
After the Cubs tied it up in the in the bottom of the first, Wil Nieves gave Washington a 2-1 lead in the second with a single to right that drove in Roger Bernadina.
The Cubs would tie the game again in the bottom of the second. Adam Dunn drove in the game-winning run with a homer over the left-center field leading off the fourth. It was Dunn's 25th career home run at Wrigley Field.
Dempster pitched eight innings and allowed three runs on four hits. After the Dunn homer, Dempster retired 14 straight before walking Nyjer Morgan in the eighth.
"I got Dempster at a good hitter's count. It was one of the rare mistakes he made today. He let the ball up and I just swung," Dunn said. "Dempster throws five different pitches. I know he got the loss, but he pitched good. He can pitch."
But Washington received better pitching on this day. After Atilano left, Brian Bruney, Tyler Clippard and Matt Capps blanked Chicago the rest of the way, with Matt Capps getting his 10th save of the season. The last time a reliever had 10 saves for the Nationals was in 2008, when Jon Rauch had 17.
Now the Nats head to Florida to face the Marlins feeling good about themselves.
"We still don't have our 'A' lineup out there," Dunn said. "We have some guys banged up, obviously. If we continue to get the pitching that we are getting and playing the defense, we are going to be fine."