Mark DeRosa was 3-for-4 with a homer and two RBIs, helping the Cubs finish their road trip 4-3 and avoid their first three-game losing streak. They are the only team in the majors that hasn't lost more than two in a row.
The Cubs, whose 40-24 record is the best in the majors, didn't get their 40th win last season until July 1, when Marquis ended a personal winless drought of nine starts with a 5-1 victory over Milwaukee at Wrigley Field to get the Cubs back to the .500 mark.
"We're playing good baseball right now and clicking on all cylinders," Marquis said. "We're going to keep battling, no matter what opponent it is, and we have a good idea of what we want to do."
Marquis (4-3) allowed an unearned run and three hits over 6 1-3 innings, walked one and struck out two in his second-longest outing this season.
"He did a real nice job. He threw strike one, stayed ahead of the hitters and won himself a ball game with a low pitch count," Cubs manager Lou Piniella said. "That's the type of performance that you expect from a veteran pitcher - obviously, not every time out, but at the same time with more consistency."
The Dodgers got their run in the first inning on a groundout by Jeff Kent that scored Juan Pierre, who led off with a single, stole second and continued to third when catcher Geovany Soto's throw bounced into center field. Marquis retired 12 in a row between Pierre's hit and James Loney's leadoff single in the fifth.
"He threw strikes, man," Pierre said. "Every time you go up there, he got that first pitch over for a strike and kept the ball down and away from the middle of the plate. We just couldn't get anything going off of him. He's a guy you can run on, but we never got guys on base to create any havoc."
Carlos Marmol relieved Marquis with the potential tying runs on base, striking out Matt Kemp and retiring Blake DeWitt with the help of a sparkling play by three-time Gold Glove first baseman Derrek Lee, who made a diving stop in the hole and tossed to Marmol for the third out while still on the ground.
"The rule is, when you're playing back and it's hit slowly, you just go to the bag," Lee said. "I was playing him straight up, and I wasn't sure DeRosa would be able to get to and make a throw in time. So I had it in my mind to go get it, because I figured I had a shot at it and I could make a little shorter throw to the pitcher. And it worked out."
Marmol got another big out in the eighth, retiring Kent on a grounder to third for the force on Pierre with men on first and second.
"Marmol's just got electric stuff. He can make a good hitter look bad," Piniella said. "But he needs to pound the strike zone a little more. These 3-2 counts are giving the manager a neck ache - but he's fun to watch."
Injury-plagued Kerry Wood, who beat out Marmol and Bob Howry for the closer's job in spring training, pitched a perfect ninth for his NL-leading 18th save in 22 attempts and fourth in the seven meetings with the Dodgers.
The Cubs are 8-20 when scoring three runs or fewer. Their last four wins under those circumstances have come at the Dodgers' expense, including all three games of a series sweep last month at Wrigley Field in which they outscored Los Angeles 8-3.
Penny (5-8) threw 110 pitches over six innings, giving up three runs and six hits. The two-time All-Star is 0-6 since beating Colorado on May 2 for his fourth straight victory, and his teammates have totaled five runs in his last four starts.
Chicago snapped a 1-1 tie with a pair of runs in the fifth. DeRosa followed Alfonso Soriano's leadoff double with an RBI single, advanced on a wild pitch and scored when Aramis Ramirez doubled inside third base for his team-high 42nd RBI.
DeRosa, the second batter Penny faced in the game, hit his eighth home run on a 3-1 pitch. It continued a couple of disturbing trends for the right-hander, who has failed to get through the first three innings without giving up a run in nine of his 14 starts this season. He has retired the side in order in the opening frame just four times.
Notes: When Joe Torre was managing Soriano in 2002 with the Yankees, he pulled out all the stops to give Soriano every opportunity to get the home run he needed to finish that season with the rare feat of 40 homers and 40 stolen bases. Before the Yankees began a three-game series in Baltimore that ended the regular season, Torre asked Orioles manager Mike Hargrove if it was OK with him Torre allowed Soriano to swing at a 3-0 pitch if the situation arose. Hargrove gave Torre his blessing, but Soriano came up empty in 15 at-bats that series - leaving him with a homerless drought of 47 at-bats over his final 11 games. He eventually joined the exclusive 40-40 club in 2006 with the Washington Nationals (46-41).