"I don't think we'll get too caught up in a loss," Kyle Schwarber said. "You're going to lose games in baseball. It was a hard-fought game, we didn't quit, we did what we wanted to do. Luckily, it clicked late for us and we put some runs on the board. They did a good job putting guys on and getting the big hit in the end."
Grichuk hit a two-run homer in the eighth and the Cubs trailed by three entering the ninth when Ben Zobrist was hit by a pitch and Jason Heyward hustled to reach on an infield single. Willson Contreras followed with a home run to tie the score at 3-3, and as if on cue, it started to rain at Busch Stadium.
"Believe me, I thought about it," Cubs manager Joe Maddon said of a flashback to the delay during Game 7 of the World Series, when Heyward delivered a pep talk to the players that sparked a win. "That's our method is to have a little bit of rain. We just didn't have a team meeting."
They also didn't get the win. On Twitter, Jon Lester tried to calm Cubs fans down, posting: "So much for an undefeated season. Glad to have the 1st start under our belt. Definitely a grind, but man it feels good to be back! #NVRQT"
The Cubs went 17-5 in April 2016, which made it seem as if they never lost a game.
"I would hope everybody in this business understands it's a marathon," Lester said. "We're not going to go undefeated. We're going to come out in Game 2 [on Tuesday] ready to go and try to win that game. That's all you can really do. With all the expectations -- we had expectations last year. From Day 1, we were supposed to win it. From three months in, we were supposed to win it. And when the playoffs started, we were supposed to win it. It's the same thing this year.
"Last year, we started 1-0," Lester said. "We'll come back [this year] and try to be 1-1 and keep moving forward. That's all you can do. Once one is over, you look to the next. It is a marathon, it's six months, if not longer. And you just have to play day by day and go from there."
One of the Cubs' mottos last year was, "We never quit." And they've kept that theme.
"I felt it was a positive day overall for us," Schwarber said. "We started the season with a grinder game, and I think that will definitely help us as we keep going down this long stretch of games."
There are 161 to go.
"You know what, this is Game 1 of 162-plus," Anthony Rizzo said. "We've got to find our identity again this year, just like we had to do last year and the year before. ... Obviously, we want to win our division and get back, but we have a lot of things to take care of before that."
• Cubs reliever Justin Grimm was expected to rejoin the team on Tuesday. He missed Sunday's game to attend his grandfather's funeral.