ST. LOUIS -- One statistic shows how effective Chicago Cubs right-hander Jason Hammel has been so far this season, both on the mound and at the plate.

With three RBIs, Hammel has driven in one more run by himself than he has allowed in 18 innings on the mound.

His fourth-inning single Wednesday night drove in both Chicago runs, and Hammel, with the help of the Cubs bullpen, protected the lead for a 2-1 win over the St. Louis Cardinals.

"We hit every day, but I'm trying anything different," Hammel said of his two hits in six at-bats this season. "I'm just trying to get the barrel on the ball. I had a pitch down and in that I could handle and basically hit it on the ground."

On the mound, Hammel allowed just five hits over six innings, giving up the only Cardinals run in the second on a single followed by a triple by Yadier Molina, the sixth of his career. Hammel (2-0) struck out six and didn't walk a batter.

Hammel's success, both on the mound and at the plate, continued two patterns for the Cubs so far this season.

He extended the streak of Chicago starters working at least six innings to all 14 games, the longest in the majors to begin the year since 1988, and tying the franchise record that stood since 1910.

At the plate, Cubs pitchers have now driven in seven runs in just 31 at-bats. It is the most RBIs of any pitching staff in the league.

"It wasn't necessarily as pretty as the line would say today, but that's the job of the starting staff to give those guys in the bullpen just one or two outs that they have to get, and that makes them better," Hammel said about his pitching performance. "So far so good."

That applies to what he and the other pitchers are doing at the plate as well.

"I just think we have fun with it," Hammel said. "We do hit in (batting practice) for a while. We take a little pride in it. We can help ourselves out, and we did it again tonight."

Hammel questioned whether he would have still been in line for the win had it not been for a throw from right fielder Jason Heyward that cut down Matt Holliday at the plate to end the fourth inning.

The Cardinals had put runners on second and third to open the inning, but Hammel retired Randal Grichuk on a pop to second. Molina then flied to right, Holliday tried to score, and he was cut down by Heyward.

Heyward, the former Cardinal, did not have a hit in the first two games of the series but still contributed to both wins with his defense.

"A lot of momentum came back to us in that moment," Chicago manager Joe Maddon said. "He constantly makes great plays. That was a big play."

After seeing the Cardinals take the 1-0 lead, the Cubs responded in the fourth off starter Jaime Garcia, who was working on a streak of 15 consecutive scoreless innings.

With one out, the Cubs loaded the bases on a walk and a pair of singles before Garcia struck out Addison Russell, bringing Hammel to the plate. The pitcher came through with the single between third and shortstop to drive in both runs.

"He's been swinging the bat well," Maddon said. "The pitchers have done a great job, they really have. You can't necessarily expect that to continue, although it's funny, technically we have guys who have some really good swings. If a pitcher makes a mistake, they have the ability to do what you saw tonight."

Garcia admitted he did not make a good pitch in that situation.

"I've got to do a better job than that," Garcia said. "It's my bad. I will try to do better next time."

The loss dropped the Cardinals to 0-5 against the two teams they expect to be their biggest competition in trying to repeat as the National League Central champions, the Cubs and the Pittsburgh Pirates. They are 7-2 against the Atlanta Braves, Milwaukee Brewers and Cincinnati Reds.

"Regardless of people claiming one team is better than another, we've just got to come out and play good baseball," Cardinals manager Mike Matheny said. "We had opportunities to win this game today. It doesn't matter who we're playing against. If we don't execute in those situations and don't get the job done and do the little things right, it doesn't matter who we're playing. We've just got to control what we can control."

NOTES: Cubs OF Kyle Schwarber underwent season-ending surgery Tuesday in Dallas to repair a torn ACL and LCL in his left knee. He was injured in an outfield collision April 7. ... Ruben Tejada made his debut for the Cardinals on Tuesday night, becoming the fourth player to start at shortstop in the first 14 games of the season as the Cardinals try to find a substitute for injured Jhonny Peralta. Through 13 games, St. Louis shortstops combined for seven errors, three more than any other team at the position in the major leagues. ... The teams will complete their first meeting of the year with a day game Wednesday. Cubs RHP Kyle Hendricks is scheduled to pitch against Cardinals RHP Carlos Martinez.