Joe Maddon earned his second ejection this season Thursday providing a spark in what became an 11-3 victory that snapped a four-game losing streak.
Maddon's theatrics came with the Cubs nursing a slim one-run lead. An inning after Maddon headed to the clubhouse Chicago broke it open during a five-run fifth that included a two-run single by Baez.
Bryant tied a season high with four hits, including a first-inning home run to the seats in right-center off Lyles.
Robel Garcia finished a double short of the cycle in his first major league start. Willson Contreras drove in three runs for the Cubs, who moved back into a tie with Milwaukee for first place in the crowded NL Central, where all five teams are separated by 3 1/2 games.
Jose Quintana (6-7) allowed three runs and six hits in seven innings to win consecutive starts for the first time since April.
Kevin Newman had two hits and All-Star Josh Bell boosted his RBI total to a major league-leading 81 with a sacrifice fly, but the Pirates couldn't pull off a four-game home sweep of the Cubs. Lyles surrendered a season-high seven runs and 10 hits, eight of them for extra bases, as Pittsburgh missed out on a chance to get back to .500 for the first time since May 31.