Samardzija threw 5 2/3 scoreless innings and hit an RBI single and Alfonso Soriano added a two-run single to lift the Cubs to a 5-1 victory over the Cardinals.
Despite the win, the Cubs (63-81) were officially eliminated from playoff contention because the National League Central-leading Reds (82-62) won Monday, beating the D-backs, 7-2.
"I didn't even know that," Cubs manager Mike Quade said. "We've talked about finishing strong. ... We've been about getting the kids better and playing well down the stretch and so far so good."
Samardzija, 25, was to have made his first start on Saturday in Florida, but he was moved up when Carlos Silva was scratched because of tendinitis in his right elbow. Samardzija scattered six hits, walked four and struck out one to pick up his first Major League win as a starter. He has two wins in relief, so no celebratory beer shower.
The difference Monday? Samardzija has developed some offspeed pitches in the Minors and was confident enough to use them.
"To me -- and I haven't seen him since Spring Training -- he did a lot of damage with his soft game," Quade said. "He threw some good splits, some good sliders. ... He did a good job against a nice club. It's a real good start."
Samardzija didn't want to go to the Minors after four April relief appearances, but he said he took advantage of the situation.
"Being down there all year, you get a lot of opportunities to throw [offspeed pitches]," he said. "It's not live or die situations all the time. Not only that but [catcher Geovany Soto] calling pitches [Monday], he showed confidence in me to throw those pitches. A lot of times that's what it takes -- throw it two or three times in a row and that gets it going for the rest of the game."
Having something in his repertoire other than a fastball can keep hitters off balance.
"He looks more aggressive, throws with more conviction and isn't afraid to baby it in the zone," Soto said.
The Cardinals had a scouting report. Samardzija was roughed up by their Triple-A Memphis team in his last Minor League outing Sept. 5 in which he gave up seven runs on eight hits over six innings. This was different.
"He was coming from all different angles and very, very hard to hit," St. Louis' Brendan Ryan said.
This outing wasn't a confidence booster. Samardzija has always been confident.
"It's almost just a deep breath," the right-hander said. "You want to see all the hard work pay off when you're out there doing everything and running and working out. It's just good to go out there against such a great team like this with the great lineup they have, to go out and have a solid outing feels good."
Aramis Ramirez, starting for the first time since Sept. 5, doubled to open the Cubs second against Jaime Garcia (13-8), moved up on Xavier Nady's single, and scored on Soto's single. Two outs later, Samardzija helped himself with an RBI single to make it 2-0.
"It had eyes," Samardzija said of his hit. "You'll take them any time you can get them."
The Cubs loaded the bases with two outs in the third, taking advantage of a throwing error by second baseman Skip Schumacher, and Soriano smacked a two-run single to open a 4-0 lead.
With one out in the St. Louis seventh, pinch-hitter Randy Winn singled off Scott Maine, who was pulled for Andrew Cashner. He struck out Albert Pujols, but Matt Holliday followed with a RBI single. Kosuke Fukudome made it 5-1 with a RBI single off lefty Dennys Reyes with one out in the Chicago eighth.
Samardzija compiled an 11-3 record and 4.37 ERA in 35 games, including 15 starts. The former Notre Dame wide receiver did make two big league starts last season, the final one coming Sept. 23. He's come a long way since hanging up his football cleats.
"Any time you have a two-sport athlete and a guy who, from what I understand, had every opportunity to play in the NFL as well, that's pretty special," Quade said. "And the competitive nature to play in the NFL? Wow. ... There's a lot of added stuff with Samardzija. But bottom line is, he has to take that athletic talent he possesses and make it work at this level, either every five days or out of the bullpen, whatever it ends up being."
Monday's game wasn't make or break for Samardzija. But he is out of options. As of now, Quade would like to see the right-hander in the rotation for the remainder of this year. He'll get another start in Florida this weekend.
"He's got a good arm, he's got a lot of intangibles," Cubs general manager Jim Hendry said of Samardzija. "He's had a real solid season. No matter what, he'll have a chance to position himself for next year."
Said Quade: "He's a big guy with a big arm, so you hope he's a big part of next year."
Samardzija knows he's not finished.
"There's still a lot left to prove," he said.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.