After dispatching Washington, Zambrano was scheduled to board an overnight flight to his homeland so he can visit the youngster in intensive care. The kid was on Zambrano's mind frequently Tuesday night.
"I was thinking about him in the first inning. I was thinking about the situation," said Zambrano, who expects to return to the Cubs on Saturday. "Every pitch I was throwing in the first inning, I was saying, 'This is for you. Don't give up. ... Pitch this game for him.' "
Chicago improved to 2-0 under interim manager Mike Quade, who took over when Lou Piniella unexpectedly retired after Sunday's game. Quade is the first Cubs manager to win his first two games since Jim Riggleman, now the Nationals' skipper, started 4-0 in 1995.
"Those guys are 2-0," Quade said, pointing to the Chicago clubhouse. "It's great. Last night was a wonderful evening, and tonight was a great game."
Zambrano (5-6) yielded a run on five hits over 7 1/3 innings, his longest outing of the year. He walked one and struck out eight.
In four starts since returning from the bullpen, the right-hander is 2-0 with a 2.25 ERA.
"I think [Zambrano] pitched with a heavy heart and [had] just as good an outing as I've seen from him for a while," said Quade.
Asked if returning to the rotation provided the former ace a new beginning, Quade said: "We'll take that fresh start and just run with it for the next six weeks."
Riggleman said Zambrano continues to be effective despite decreased velocity.
"We didn't really have a lot going against (Zambrano). He pitched good," Riggleman said. "He's a little different style pitcher than he was maybe in past years where he was throwing in the high 90s. Today, he was more in the 90 [mph] area but really worked fast, pitched effectively, had quick innings and got ground balls."
The Nationals have lost three straight games and dropped a season-worst 20 games under .500.
Ryan Zimmerman lined out to right for the game's final out with the tying run on second base.
Soriano's three-run homer put the Cubs ahead in the second. Jeff Baker and Geovany Soto singled before Soriano sent an 0-1 John Lannan pitch into the left-field stands for his 20th. It was his first homer since Aug. 1 and gave him nine straight seasons of 20 or more home runs.
"He's got the ability to elevate the ball in that part of the park right there," Riggleman said of Soriano's third homer in five career games at Nationals Park. "John battled him tough, threw him some good pitches. But Soriano just won that battle."
Zimmerman's RBI single got the Nationals within 3-1 in the third. Alberto Gonzalez led off with a single and beat the throw to second on Lannan's sacrifice attempt. Zimmerman then singled to center.
A two-run shot by Colvin made it 5-1 in the fourth. Soriano reached on shortstop Gonzalez's throwing error and Colvin homered to right-center on Lannan's first pitch.
Lannan (5-6) was pulled after allowing five runs on seven hits in five innings. He struck out three.
Colvin's 19 homers lead major league rookies and are the fourth-most by a rookie in Cubs history. ... Before the game, the Nationals placed RHP Stephen Strasburg on the 15-day disabled list with a right forearm strain and recalled RHP Collin Balester from Triple-A Syracuse. ... Chicago optioned RHP Justin Berg to Triple-A Iowa on Tuesday and selected the contract of LHP Scott Maine. ... Before the third, Zambrano had not allowed an earned run at Nationals Park in 14 2/3 innings. He is 3-0 with a 0.47 ERA in four career starts at Nationals Park. ... With runners on first and second and the Cubs in an exaggerated shift against Washington's Adam Dunn in the eighth, Nyjer Morgan jogged to third uncontested. It was ruled defensive indifference, not a stolen base.