It wasn't Jake Arrieta's velocity dip that burned the Cubs Saturday afternoon.
And it's hard to blame the 24 mph winds blowing straight out to centerfield, creating a great hitters' environment at Wrigley Field.
The Cubs bullpen served up five runs in the top of the seventh inning as the Pittsburgh Pirates rallied to pull off an 8-7 win over the defending champs.
After Arrieta surrendered three runs in 5.2 innings and departed with the Cubs up 6-3, Brian Duensing and Pedro Strop were lit up in the seventh with the big blow a three-run homer off the bat of Andrew McCutchen on a 2-2 Strop slider.
Strop has now allowed eight baserunners, four runs and two homers in his four innings on the 2017 season, so are the Cubs concerned?
"Honestly, I'm not," Joe Maddon said. "He looks normal to me. He's got great stuff. He deosn't have good stuff. He's gonna be fine. He's gonna work through it. He'll get through it on the other side and that slider's gonna be where it's supposed to be.
"I'm OK, honestly, with the slider being hit for a home run there as opposed to a fastball. That's his pitch in that moment. He just got it in a bad spot and give McCutchen credit. I like the choice of pitch, the execution wasn't there."
The Cubs offense also sputtered late after jumping out to a big lead early on with four runs in the first and two in the third.
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Kris Bryant hit the scoreboard on a two-run shot in the first inning and Addison Russell drove in three with a triple and a double.
But the Cubs' bats went silent from there until Bryant's shot into the basket in left-center with one out in the ninth inning.
The Pirates started off the game flat with a crucial error, passed ball and misplays in the outfield but they turned things around to win their second straight against the Cubs.
This is the first series of the 2017 season the Cubs have dropped. The finale comes Sunday afternoon with Jon Lester pitted against Jameson Taillon.