And yet the Cardinals are in position to complete a three-game sweep of the Cubs on Sunday night after erasing deficits of 4-0 and 6-4 on Saturday before Kolten Wong's two-run walk-off homer in the 10th inning capped an 8-6 victory Saturday.
The win, however, cost the first-place Cardinals center fielder Tommy Pham, who left in the second inning with right groin tightness, catcher Yadier Molina, who left the game in the ninth inning after being hit by a foul tip, and closer Bud Norris in the 10th inning with a triceps injury.
According to the St. Louis Post-Dispatch, manager Mike Matheny told reporters that all three players were candidates for replacements.
Despite the injuries, though, the Cardinals improved to 3-1 this season against the two-time defending National League Central champions.
"I've never (played) in the World Series or those kinds of games," Cardinals outfielder Marcel Ozona told reporters after he tied the game in the ninth inning with a two-run double. "This feels like more of a regular game."
But after trailing twice Saturday, including by two runs late, St. Louis' latest win felt like so much more than a normal game in early May.
"I'm telling you, we never feel like we're out of it," Cardinals third baseman Matt Carpenter told reporters, according to the team's official website. "This was a really great win for us, and everybody had a piece of it."
Michael Wacha (4-1, 3.62 ERA) will try to deliver the series sweep for the Cardinals, who have won four straight games.
Wacha won four straight games in April before he registered a no-decision last week against the Chicago White Sox when he allowed two runs and scattered five hits in five innings. Wacha is 4-7 with a 6.41 ERA in 16 games (14 starts) against the Cubs.
The Cubs will enter Sunday's primetime showdown having lost four straight games after putting together five straight victories. The Cubs finally showed promise offensively Saturday, when they snapped a nine-game string of games in which they scored three or fewer runs.
But after blowing two different leads as their slide continued, the Cubs will attempt to get back on track in Sunday's series finale.
The back and forth Cubs performance has been difficult to predict after they finished a 5-2 homestand despite struggling to score runs.
Manager Joe Maddon found silver linings in the Cubs' recent roller coaster ride and continues to point to how early in the season his team's Jekyll and Hyde act has surfaced.
"Regardless of what your plan may be, teams are going to go through these moments," Maddon told reporters before Saturday's game, according to the Chicago Tribune. "It just happens to be ours right now. I want to continue to work like we've been working. I believe in our guys and believe in our methods. It's just the ebb and flow of the season. Right now, it's our turn. We'll come out of it and be fine."
Jon Lester will take the mound for the Cubs. Lester (2-1, 2.73) has already beaten the Cardinals once this season when he threw six innings and allowed an unearned run and two hits April 19. Lester is 6-4 with a 3.16 ERA in 15 career starts against the Cardinals.