By the way, Soto also did his job at the plate, hitting a solo homer, his 15th, to lead the Cubs to a 7-1 victory over the St. Louis Cardinals, and open a 3 1/2-game lead in the National League Central.
All-Star Aramis Ramirez drove in three runs for the Cubs, who rebounded from a tough loss Saturday.
"It's going to happen," manager Lou Piniella said of the day before, when the Cubs blew a two-run lead in the ninth to lose, 5-4. "They happen a few times a year. The problem is you don't like them when they happen, but you have to accept it. To the credit of this team, we came back today and played aggressive and played a real good ballgame. We got some timely hitting and really good pitching, and we bounced back. We can enjoy our day off tomorrow a little more."
Soto, one of a franchise-record seven Cubs selected to the National League All-Star team along with Ramirez, led off the eighth with his blast off Russ Springer. His 15 homers are the most by a Cubs rookie since Mel Hall hit 17 in 1983.
"I don't really know how to feel," Soto said of his All-Star selection. "Do I feel excited, nervous, happy? It's kind of surreal right now. Right now, I don't know what to expect."
Ramirez had doubled in the second and scored on Mark DeRosa's single against former Cub Todd Wellemeyer (7-4). Ramirez also hit an RBI single in the third and hit sacrifice flies in the fifth and the ninth. He leads the team with 60 RBIs.
Derrek Lee added a two-out, RBI double in the Chicago seventh, scoring Kosuke Fukudome. It was nice to have timely hitting.
"I think hitting is contagious, and we've seen that all year," Soto said. "We had to pick it up on the road, and we did it a little."
Marshall (1-2) picked up the win, giving up one run on six hits over six innings while striking out four. One of those hits was a solo homer by Ryan Ludwick with one out in the sixth. He'll stay in the rotation, getting his next start Saturday against the San Francisco Giants. Sean Gallagher also stays in the rotation, and Jason Marquis will start Friday.
Marshall was the star Sunday.
"Over the two years I've been here, that's as good as I've seen him throw the ball," Piniella said.
"It was good -- it was hot," Marshall said. "I made some pitches when I needed to and got out of a couple jams.
"Hopefully we can use the momentum from this game and I can carry it into my next start, and the team can carry it into Tuesday."
This trip signaled the last of the tough road junkets for the Cubs. With the win, the Cubs took the series, their first away from home since taking two out of three at Toronto on June 13-15. Chicago's 53 wins are the most before the All-Star break since the 1977 team won 54 in the first half.
"This series isn't going to decide the winner in the National League Central," Piniella said of the showdown with the Cardinals. "There's too much baseball to be played.
"What we need now is to stay hot at home. We played really good baseball in the first half at home, and we need to continue that."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.