"Early, his fastball had a little different life than what we've seen," Counsell said.
Though impressive, Pena's early dominance didn't last.
Cubs shortstop Addison Russell nearly hit a home run to open the third inning -- which ended thanks to a clutch 3-6-3 double play -- and, in the fourth, Pena surrendered a solo homer to Anthony Rizzo.
Miscommunication between center fielder Jordan Schafer and right fielder Domingo Santana on a high fly ball extended the fifth inning and ended Pena's day.