CHICAGO -- Miguel Montero said he had been ready for this moment since mid-afternoon.

Entering Saturday night's National League Championship Series opener as a pinch hitter with two out and bases loaded in the eighth inning, Montero launched an 0-2 pitch from reliever Joe Blanton for a grand slam home run as the Cubs rolled to an 8-4 victory over the Los Angeles Dodgers.

"To be honest, I started getting loose about three o'clock," Montero said. "As a kid, you dream of these situations and that's what you live for."

It was the first time in major league history that a pinch-hit grand slam provided the game-winning run in a postseason game.

Dexter Fowler added a solo shot in an explosive eighth as Chicago scored five times on the way to a 1-0 NLCS lead over the Dodgers.

Chicago snapped a 3-3 tie after giving up the lead earlier in the inning after closer Aroldis Chapman was hit for two eighth-inning runs when he entered with bases loaded.

Chapman struck out the first two batters but gave up a two-out single to Adrian Gonzalez that drove in pinch hitters Andrew Toles and Chase Utley to tie the game.

"Throughout his career, Adrian's gotten so many big hits," said Dodgers manager Dave Roberts. "Big hit and, yeah, right there I thought we were going to win it."

But Ben Zobrist opened the Cubs' eighth with a double to deep right and Jason Heyward and pinch hitter Chris Coghlan were intentionally walked by Blanton, a right-handed reliever.

That set the stage for the left-handed batting Montero, pinch hitting for Chapman. He sent Blanton's 0-2 pitch to right to clear the bases. Fowler followed with a solo homer to right.

"I would do the same thing all over again," Roberts said. "Ten times out of 10 I would take Joe Blanton against Montero. (But) he took a good swing on an 0-2 pitch and it's going to happen. That's baseball."

Chapman blew a save but still earned the victory despite giving up the lead.

"Give Chappy credit for keeping it at two," Cubs manager Joe Maddon said. "When you've given up two runs to tie the game, tendency is maybe the mental letdown. But he did not permit that to happen."

Blanton took the loss after working just two-thirds of an inning and allowing five runs on four hits while walking a pair.

Cubs starter Jon Lester allowed one run in six innings and retired 12 of the last 13 batters he faced. But he received a no-decision after allowing just four hits, walking one and striking out three.

"I thought that tonight Jon really wasn't on top of his game," Maddon said.

Dodgers starter Kenta Maeda also had a no-decision after an abbreviated four-inning outing.

The Dodgers loaded the bases with none out the eighth against Chicago pitchers Mike Montgomery and Pedro Strop, leading to Chapman's fifth playoff appearance.

Fowler was 2-for-5 with an RBI and two runs scored, Javier Baez went 2-for-4 with an RBI and a run scored while Kris Bryant was 2-for-4 with an RBI.

Toles doubled home Joc Pederson with one out in the ninth off Hector Rondon to close the margin.

The Cubs quickly hit Maeda for a first-inning run after Fowler's leadoff single to center. Bryant lined a 1-2 pitch off the left-field wall past the outstretched arm of the Dodgers' Howie Kendrick for a double. Fowler sprinted home while the ball returned 30 feet in before Pederson picked it up.

The Dodgers were denied a tie in the second inning. With runners at first and second and two out, Maeda dribbled a single past Addison Russell and Bryant but Zobrist rifled a throw to the plate and catcher David Ross tagged Gonzalez to close the frame.

Chicago made it 2-0 in the second as Heyward tripled into the right-field corner and scored as a short fly by Baez dropped into center for a double.

Baez reached third on a Ross sacrifice and made it 3-0 as Dodgers catcher Carlos Ruiz tried to catch him off base with a snap throw to Justin Turner. Baez bolted home with a steal as Turner's return throw to Ruiz was late.

Fowler made two defensive gems in the early innings -- diving catches that prevented extra-base hits by Dodgers batters -- among several by the Cubs.

Maeda was pulled in the fifth for pinch hitter Andre Ethier, who promptly got one run back for the Dodgers with a two-out solo home run to the left-field basket.

"It's a game we can't lose and being behind by three runs it just turned out that the pitcher's spot was up, so the team had to prioritize on the hitters," Maeda said through a translator.

Maeda allowed three runs on four hits, struck out three and walked a pair.

The series continues Sunday night in Chicago and shifts to Los Angeles on Tuesday and Wednesday for Games 3 and 4. All games are set to being at 8:08 p.m. (ET).

NOTES: Dodgers LHP Clayton Kershaw will start Sunday's Game 2 of the NLCS, manager Dave Roberts confirmed on Saturday. Kershaw last worked on Thursday, getting the final two outs in relief of Los Angeles' NL Division Series clincher over the Giants. ... The Dodgers added LHP Alex Wood and INF/OF Kike Hernandez to their NLCS roster while deactivating INF Charlie Culberson and C Austin Barnes. Hernandez was in Saturday's starting lineup. ... Los Angeles and Chicago have met only once in the postseason, a three-game NLDS sweep by the Dodgers in 2008. ... This is the second straight year the Cubs have reached the NLCS. The New York Mets recorded a four-game sweep in 2015. It's also just the fourth time Chicago has been in a league championship round, all series losses. ... The Cubs added LHP Rob Zastryzny to their NLCS 25-man roster on Saturday while INF Tommy La Stella was removed. ... RHP Kyle Hendricks, owner of a big league-leading 2.13 ERA, makes Sunday's start for Chicago. Hendricks said he was fine after being struck on the forearm by a line drive by San Francisco's Angel Pagan last week.