The Mets silenced the Cubs with their new style — a complete, quick-strike offense that would have seemed so unlike them just three months ago. Back then, the Mets’ threadbare lineup gasped for runs, threatening to waste all their dominant pitching. Healthy and fortified now, the hitters can practically do no wrong.

The Mets are at their best in the first inning, often because that is when Murphy bats. They scored in the first inning of every game of this N.L.C.S. — nine runs in all, an advantage that helped them make history.

An ultimate sweep — in which the losing team never leads, even for a moment — is rare for a best-of-seven series. It has happened only five other times in major league history, and never before in a best-of-seven N.L.C.S.

The Cubs’ hopes of holding a lead, let alone winning a game, died early on Wednesday. Granderson wore down starter Jason Hammel, slapping his seventh pitch to left for a single. With two outs, he stole second, continuing to exploit an edge the Mets uncovered in their advance scouting.

Cespedes walked and Duda came to bat, lugging a .125 postseason average with no extra-base hits. He took a close pitch on 2-2 that showed, if nothing else, that Duda could control his plate discipline, a tenet of the Mets’ hitting philosophy. His reward came on Hammel’s next pitch: a fastball down the middle that Duda obliterated.

The ball took flight, whistling as it rose over the infield and crashing into the center-field seats, a few rows up, just to the left of the hitter’s backdrop. Soon it was rolling back along the outfield grass — discarded, per Wrigley tradition. If only the fans could evict the Mets’ players as easily.

The next hitter, Travis d’Arnaud, sent another screamer into the right-field seats: 4-0, Mets, after only six batters. Hammel was gone after 11, in the second, when Duda drove in two more by doubling off another 3-2, two-out fastball, this time from Travis Wood.