ST. LOUIS (AP) -- For the second straight game, the Chicago Cubs squandered a nice lead. Once again, there was not enough pitching, especially against a team off to the best start in the majors.
"We have to do a better job of holding leads," manager Joe Maddon said after the Cubs couldn't hold a three-run lead and lost their fourth straight, 7-4 to the St. Louis Cardinals on Tuesday night. "It's pretty simple stuff.
"That middle part of the game is something we've got to get better with."
Pinch-hitter Mark Reynolds doubled off the wall in center field to snap a tie in the sixth inning and the Cardinals won their eighth straight.
Matt Carpenter of St. Louis tied the game with a three-run homer off Kyle Hendricks in the fifth and finished with four RBIs.
"He's one of their best hitters and he's one of the best hitters in the league right now, too," Hendricks said. "Tough guy to get out, and I've just got to make good pitches to him and I didn't make a good pitch.
"Can't make bad pitches to him."
The bottom of the order hurt Hendricks. Kolten Wong, the No. 8 hitter, doubled to start the fifth and Hendricks hit pinch-hitter Peter Bourjos to set the stage for Carpenter's homer.
"I've got to change something up, find it and get out of it somehow," Hendricks said. "Hitting guys, walking guys, that's not what I do.
"The feel is just not there."
Wong added an RBI in the seventh on an infield single, his third hit of the game.
Mitch Harris (1-0), a 29-year-old rookie and former Navy lieutenant, worked a scoreless sixth for his first career victory. Trevor Rosenthal earned his ninth save in 10 chances.
Anthony Rizzo had three hits and a walk but grounded out with the bases loaded against Miguel Socolovich to end the eighth. Starlin Castro had two RBIs on a forceout in the fifth when the Cardinals couldn't quite turn a double play and rookie Kris Bryant scored from second.
The losing streak is a season worst for the Cubs, who hadn't dropped three straight before Monday.
"I'm a really process-oriented guy and I really believe in our people," Maddon said. "You've just got to keep putting them out there until it works properly."
Yadier Molina added two hits and an RBI for the Cardinals, whose major league-best 20-6 start is a franchise best since 1900.
Besides trailing 4-1 in the fifth inning Tuesday, the Cardinals were behind 5-0 in the first and 8-4 in the fifth of a 10-9 win Monday.
Reynolds, who hit a grand slam in Monday's comeback, had been 1 for 8 with six strikeouts against Edwin Jackson (1-1) before his go-ahead hit Tuesday.
Harris is the just the second major leaguer from the Naval Academy and the first since Nemo Gaines in 1921 with the Washington Senators.
Cubs: Jon Lester (1-2, 4.71) was 2-0 with a 0.59 ERA for the Red Sox in the 2013 World Series against St. Louis. He's 0-1 with a 3.86 ERA in two regular-season starts, including opening night at home this year.
Cardinals: St. Louis has scored just 10 runs in five games started by Lance Lynn (1-2, 3.07). The right-hander is 4-1 with a 1.14 ERA at home against the Cubs.
Cubs: GM Jed Hoyer opted for 13 pitchers after Chris Denorfia (hamstring) was placed on the DL, saying "We're a little bit gassed."
Cardinals: Set-up man Jordan Walden, on the DL with a biceps injury, was getting a second opinion on an MRI. GM John Mozeliak said Walden was "leaning toward" trying to pitch through it.