"I had a steak and a salad for lunch and then a bratwurst before the game," Marshall said of his ritual, which he started in late April. "It's been good."
So has Marshall, who hasn't lost at Wrigley Field in four starts. Marshall (3-1) retired the first 10 batters and had a no-hitter going until Alfonso Soriano led off the sixth with a single to left. Marshall walked four and struck out six in six innings. He gave up nine runs in 3 2/3 innings in his last start at San Francisco. The quick rebound impressed his veteran teammates.
"He didn't have his best command, but he battled out there," said center fielder Juan Pierre, who made a great diving catch to rob Soriano of a hit in the fourth. "That's the sign of a pitcher that's maturing a lot."
Marshall said he didn't feel his fastball was sharp enough, so he relied on his changeup and the rest of his offspeed stuff.
"I was doing pretty good changing speeds in different counts," Marshall said. "It was just a matter of me building up my confidence and having command of all my pitches."
The 6-foot-7 left-hander won for the first time in four starts and the Cubs improved to 6-2 when he pitches. Carlos Zambrano threw eight scoreless innings in Chicago's 4-0 win over the Nationals on Tuesday.
"The main thing is you're getting two great games by your starting pitcher back-to-back," Cubs manager Dusty Baker said. "Hopefully this can become contagious to everybody."
Scott Williamson, Bob Howry and Scott Eyre each worked an inning, with Eyre striking out the side in the ninth for the Cubs. It was the first combined one-hitter for the Cubs since June 26 against the White Sox, whom the team faces this weekend.
Walker's two-run single capped off a three-run second inning for the Cubs, who won two in a row for the first time since winning three straight on April 23-25.
The Cubs won their first series since taking two of three against Florida on April 24-26. The team had lost five series and split one since then.
The Nationals have lost six of seven games. They hadn't been shut out in consecutive games since St. Louis did it on Aug. 27-28.
"We just can't put anything together as far as offense is concerned," manager Frank Robinson said.
Zach Day (2-4) took the loss, giving up three earned runs and eight hits with three walks in four innings.
"We're struggling badly," Jose Vidro said. "It's not just the hitting, its just everything, no 'Ws,' no nothing. We're struggling so badly right now that it's not worth watching."
The Cubs hadn't picked up consecutive shutouts since June 26 and June 28, when they beat the White Sox and Brewers each 2-0.
Jacque Jones led off the second with a double off Day. He went to third on a sacrifice and scored on a suicide squeeze bunt by Ronny Cedeno, who reached safely. Marshall followed with a single, Matt Murton walked to load the bases and Walker hit a hard single up the middle to make it 4-0.
Marshall's steadiness helped Baker feel comfortable calling plays like the suicide squeeze.
"It starts with starting pitching," he said. "If you're not giving up anything, you can play that kind of ball. If you're behind early or behind a lot, it kind of puts you behind the eight ball, so to speak."
The Cubs took the lead in the first when Pierre singled, stole second and took third on a grounder before scoring on third baseman Ryan Zimmerman's error.
The Nationals managed just three walks and a fielder's choice before the sixth. They had runners at first and third with two outs in the fifth but pinch-hitter Robert Fick got called out on strikes to end the threat. Fick was quickly ejected by home plate umpire Marvin Hudson for arguing the call. He was pinch hitting for Day.
The game's start was delayed for almost an hour due to rain.
Robinson almost missed the game due to severe back spasms.
"My back is OK," he said. "I was signing an autograph. I don't know what happened."
- The Nationals' medical director, Dr. Bruce Thomas, was fired Wednesday by the D.C. Sports Medicine Group, which is in its first year as the primary medical provider of the team. Thomas was hired by the group at the club's request and had worked for the Nationals/Montreal Expos for 4½ years. He plans on moving back to his home in Florida, according to the team.
- Cubs 3B Aramis Ramirez left the game after the third inning with a mild lower back strain. Baker said Ramirez wrenched his back in the second. He is listed as day to day.
- Nationals outfielder Jose Guillen left the game with a right hamstring strained in the fourth inning. He is day to day.
- The Cubs met with the team's head of security to discuss Tuesday's incident in which a woman threw a ball that nearly hit Jones in the face.
- Kerry Wood will start Thursday for the first time since July 20. He has been on the DL since having arthroscopic surgery on his shoulder last August.