"It's in place for a reason," Hurdle said of the expanded replay system, "for plays like that. Everyone wants to get plays right."
Polanco had grounded to short with two outs, and Starlin Castro's throw to first was deemed in time by umpire James Hoye.
Upon replay review, the call was overturned -- and Polanco had an 11-game hitting streak to start his career. That infield single was his only hit of the game.
"He looked safe," said Hurdle, explaining as simply as possible his decision to issue the challenge, "and it turned out to play very big for us."
Josh Harrison followed with a home run to extend the Pirates' lead to 5-2 lead.
"As a side note," Hurdle said, "the kid's got a hitting streak on the line but, most importantly, he was safe at first, then we got the home run for some separation."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.