CHICAGO -- The Pittsburgh Pirates had just blanked the Chicago Cubs 4-0 for their eighth straight victory on Saturday.

The young Cubs partied anyway.

Chicago players, coaches, management and families gathered in front of the home dugout for a Champagne-soaked celebration of the Cubs' first postseason appearance since 2008.

"I could see the abilities here, but we had to go out and actually do it," manager Joe Maddon said. "To do it with this many young guys is unusual; it really is. But you know they're a little bit different. Beyond being just very good players, they handle the moment really well. They're very humble; they're very accountable."

The Cubs clinched the second National League wild-card spot late Friday night as the defending World Series champion San Francisco Giants -- the final surviving wild-card contender -- lost 5-4 to the Oakland Athletics.

Few were immune from dousing along the third-base line, including owner Tom Ricketts, who smiled in between swigs.

"It tastes great," he said.

Jordy Mercer's three-run homer in the fifth inning gave the Pirates all the runs they needed in what was a potential National League wild-card playoff game preview.

Mercer's fifth-inning home run came off Cubs right-handed starter Jason Hammel, who didn't make it out of the inning.

Hammel (9-7) officially worked four-plus innings and gave up three runs on seven hits while striking out two as the Cubs went on to use seven pitchers.

The win was the second straight over the Cubs for Pittsburgh (95-60). Chicago (89-65) fell for the third straight game.

"It's definitely a good time to get hot, definitely a good time to play sound, fundamental baseball," Mercer said. "Everybody one through nine, it seems like, is putting good at-bats together, too, and obviously our pitching speaks for itself. It's done that all year."

The Pirates hold the top wild-card position and also remain in contention for the NL Central title as they chase the St. Louis Cardinals.

Left-handed starter Francisco Liriano (12-7) went deep for the Pirates, departing after 7 2/3 innings with runners on first and second. Left-handed reliever Antonio Bastardo got first baseman Anthony Rizzo on an inning-ending fly to center to preserve the shutout.

Liriano allowed four hits, walked three and struck out nine.

"I got better command of the fastball and I was throwing it down in the zone and not trying too hard to make some pitches," Liriano said. "A better command of the fastball was the key for me."

Each team had runners in scoring position through four scoreless innings.

Mercer finally broke the shutout with his three-run homer with none out in the fifth. The shot, his third of the season, came on a 1-0 pitch and landed in the left-field bleachers while bringing home catcher Francisco Cervelli and first baseman Pedro Alvarez.

Hammel gave up five straight hits -- including two more after Mercer's homer -- and departed in favor of right-handed reliever Justin Grimm.

Grimm got one out and walked center fielder Andrew McCutchen to load the bases before he was replaced by right-hander Trevor Cahill, who struck out second baseman Neil Walker to end the inning.

First baseman Sean Rodriguez singled home Cervelli with an insurance run with one out in the eighth as the Pirates made it 4-0.

NOTES: With the National League wild-card field tentatively set, the remaining question is where the game will be. Pittsburgh has a 5 1/2-game lead over Chicago and would host. There are a dwindling number of games to play -- seven for the Pirates and six for the Cubs. ... Pittsburgh is 2 1/2 games out of first place in the NL Central and also has a chance to catch the Cardinals for the division title. ... The Pirates are 35 games above .500 for the first time since the 1991 team went 98-64. ... The Pirates will send RHP A.J. Burnett (9-5, 3.15 ERA) against Cubs Cy Young candidate Jake Arrieta (20-6, 1.88) in the series finale Sunday. ... The Cubs celebrated their overnight playoff clincher with a pregame bow in front of cheering fans while the video board featured season highlights. ... The postseason appearance will be the fifth for Cubs manager Joe Maddon, who took the Tampa Bay Rays to the playoffs in 2008, '10, '11 and '13. Lou Piniella was the last manager to take the Cubs to the postseason, in 2007. ... No matter the outcome of weekend games, Chicago still has the season edge over Pittsburgh, with a 10-8 overall lead.