The World Series champions have won nine of their last 10 interleague games. The NL Central leaders have won five of seven overall.
Happ hit an RBI single in the first inning and added a solo homer in the fourth. In the sixth, Happ drew a leadoff walk from Danny Barnes (2-4) and later scored on a two-out single by Javier Baez for the go-ahead run.
In his seventh start since being acquired in a trade from the White Sox, Quintana (4-2) gave up two runs and four hits. He struck out eight and walked two.
Cubs closer Wade Davis pitched a perfect ninth for his 26th save in as many chances. He tied the franchise record for consecutive saves opportunities converted.
