Baez helped the National League Central-champion Cubs reach triple digits in victories for the first time since 1935. He hit his second career grand slam in the fourth inning to extend Chicago's lead to 5-0 and his two-run single capped a six-run sixth that made it 11-0.
Hendricks (16-8) dropped his ERA to 1.99 by scattering seven hits, striking out five and walking none. He has not allowed more than three runs in 22 consecutive starts.
Kris Bryant hit a two-run home run, his 39th, in the sixth to draw within one of NL leader Nolan Arenado of Colorado.
The Pirates saw their hopes of a fourth consecutive postseason appearance dim even further with their third straight loss. They entered the day 4 ½ games out of the second NL wild card with seven games to play.
Rookie Chad Kuhl (5-4) was rocked for five runs and eight hits in three innings as his string of nine consecutive starts of giving up three runs or less ended.
