The Chicago Cubs had this one in hand for seven innings. Then Arizona's bench got involved, and it all came apart in the span of two swings.

Chicago led 4-0 into the eighth inning Tuesday night at Chase Field, built on a three-run homer from Ian Happ in the fourth and an RBI single from Michael Busch. But the Diamondbacks stormed back: Gabriel Moreno's RBI double and a two-run single from Geraldo Perdomo pulled Arizona even, setting the stage for rookie Ryan Waldschmidt — sent in to pinch-hit — to end it. Waldschmidt crushed a 2-1 slider off reliever Jacob Webb 408 feet for a walk-off two-run homer, sealing a 5-4 win, according to ESPN.

"I was ready the whole time... tried to get as many swings in as possible... just trying to be ready for any moment that my name was called," Waldschmidt said after the game.

"JUST TRYING TO BE READY FOR ANY MOMENT MY NAME WAS CALLED"

A Habit, Not a Fluke

The win was Arizona's MLB-leading 40th comeback victory of the season, a mark that speaks to a roster that has made a habit of refusing to fold. For Waldschmidt, it was also his second walk-off homer of the month — he beat the Los Angeles Dodgers with one on Aug. 7 — making him, per MLB.com, the first rookie in franchise history to deliver multiple walk-off homers in a single month.

The loss stings for Chicago, which entered the night holding a National League Wild Card spot and now has to answer questions about a bullpen that couldn't hold a four-run cushion. The Cubs' playoff math isn't broken by one blown lead in late August, but with the race tightening, blown four-run leads are exactly the kind of game that comes back to haunt a team in September, as Sports Illustrated noted in its recap.

For Arizona, the win keeps its own postseason hopes alive heading into the stretch run, and gives the club another data point in an increasingly compelling case that Waldschmidt — a midseason call-up — has become one of the most clutch bats on the roster.