The view from the upper deck as Cubs players begin their celebration after beating the St. Louis Cardinals to win the National League Division series in October 2015 (Chronicle photo)

The Chicago Cubs couldn’t officially clinch their latest playoff berth with a victory at home on Thursday but that hardly stopped fans from a midnight celebration.

The Cubs had dropped a 5-4 decision to the Milwaukee Brewers,  but it simply delayed the inevitable for a team with baseball’s best record and an insurmountable lead over second-place St. Louis.

When the San Francisco Giants beat the Cardinals 6-2 as Thursday turned to Friday, it knocked St. Louis out of contention, gave the Cubs their division crown and launched impromptu partying  at nearby Wrigleyville bars.

The festivities continued on Friday as the Cubs and fans officially celebrated the first step in what they hope is a run to their first World Series championship since 1908.

The Chicago Cubs are fortunate to be in the post-season business in the 21st century.

If this was a couple of generations ago, say in 1969, the Wrigley Field groundskeeper would have put in a new order for sod had there been a clincher. The fans would have rioted and stormed the field by the thousands, ripping up the grass and likely appropriating the bases and pitching mound.

Swarming the field like ants to an abandoned picnic lunch was the custom through much of baseball in the mid-20th century. And in Wrigley Field, the occasion did not even require a first-place lockdown for the mobs to burst forth. Perhaps because Cubs fans did not have such a cause for celebration, they found other regular-season feats to party hearty on the field.

Most of the fans’ mob scenes in recent years have been transferred to the bars largely along Clark Street, which has now replaced Division Street – where the 1990s Bulls were lauded — as the championship party capital of the city. Blackhawks fans toasted their Stanley Cup titles in Wrigleyville over the past six years.

The Cubs had a good ol’ time beating the hated Cardinals at Wrigley Field to reach the National League Championship Series last year.

But there is something even more special about merely getting to the post-season in previous seasons and locking it down at home before the adoring masses, including a two-for-the-price-of-one deal:

1998 

his wild-card play-in victory in Game No. 163 might have been the most surprising, most hastily-put-together celebration in Wrigley Field annals.

Boosted by Sammy Sosa’s home-run duel with Mark McGwire and Kerry Wood’s “Kid K” rookie whiff season, the Cubs seemed to be in good shape for the wild card with an 87-67 mark on Sept. 17. But then a sweep by the lowly Reds at Wrigley Field triggered a late slump. When poor Brant Brown dropped a potentially game-ending fly ball in left field to lose a game and send WGN’s Ron Santo into on-air anguish in Milwaukee six days later, the Cubs seemed doomed with three losses in their final four games. They actually walked off the field in Houston Sept. 27 believing they were knocked out of the post season with the Giants drawing the final playoff spot.

But moments later, hundreds of miles away, future Cub Neifi Perez, then a Rockie, slugged a walkoff homer against the Giants at Coors Field, sending the season into overtime. The ESPN-televised play-in game would be staged on Monday night, Sept. 28, at Wrigley Field. As word of the bonus contest spread through Chicago late in the afternoon on Sept. 27, crowds rushed toward the Wrigley Field windows to gobble up available tickets.

Get your Cubs stuff right here. A vendor offers a variety of shirts, hats, flags and other Cubs keepsakes outside the Wrigley Field bleachers prior to a National League Division Series against the Cardinals. (Chronicle photo).

The postseason fate of the Cubs was in the hands of … Steve Trachsel. But the right-hander had good seasons in even-numbered years. He was effectively wild, walking six in 6 1/3 innings – but allowing just one hit. Late-season clutch-hitting acquisition Gary Gaetti was again the hitting hero with a two-run homer as a ghostly illuminated image of Harry Caray, who had died earlier in the year at 84, was festooned above a rooftop on Sheffield Avenue.

Pitcher Terry Mulholland may have had the biggest heart of any Cub. He had thrown 121 pitches as the starter in Sunday’s loss. But the earthy lefty volunteered for one-batter relief duty. Manager Jim Riggleman initially doubted him. To prove he had a bit of gas in the arm, Mulholland launched a strong heave from the infield to the left-field bleachers pre-game. Taking him up on his offer, Riggleman summoned Mulholland to face Barry Bonds leading off the ninth with a 5-3 lead. Bonds flied deep for the out.

Two batters later, exhausted but game closer Rod Beck had retired the Giants, trigging a huge on-field celebration in the first Cubs home clincher at night. No matter the Cubs subsequently were swept by a superior Braves team helmed by Greg Maddux. The image of the first playoff berth in nine seasons, after so much Tribune Co. mismanagement that cost Maddux’s services, is still emblazoned in any witness’ memory.

2003 

Who’d think the lucky fans holding tickets to the second-to-last Wrigley Field home game of the season would double their pleasure – see an old-fashioned twin bill and their heroes clinch the NL Central by sweeping the pair of games?

But that’s  the Cubs Experience, where strange twists and Mother Nature’s effects are always second nature.

The “In Dusty We Trusty” debut season had gone decently in the first half. However, the Cubs under Dusty Baker bumped along around .500 behind the Cardinals and Astros much of July and August. On Sunday, Aug. 31, after being blanked 2-0 at home by longtime nemesis lefty Doug Davis of the Brewers, the Cubs were still just 69-66.

Then they stepped on the gas. A memorable five-game series against the Cards at Wrigley Field Sept. 1-4 produced four wins and a famed mid-game blue streak between Baker and Tony La Russa in each of their dugouts. The hot Cubs finally jumped into first place on Sept. 23 in Cincinnati and had a chance to win the division during a season-ending three-game weekend series with the Pirates at Wrigley Field.

However, the Friday, Sept. 26, game was rained out with a full house of 40,000 already in the stands. Realizing they could not exchange their tickets for sold-out contests the next two days, some of the natives truly grew restless. Police were called into the ballpark to keep order.  The rainout set up the Saturday doubleheader. With so much at stake, management opted not to further strain the team by playing a day-night split twin bill with two separate gates.

First baseman Anthony Rizzo has a sly, satisfied smile as he listens to a question at a post-game press conference after the Cubs beat the St. Louis Cardinals in the National League Division Series in October 2015. (Chronicle photo)

Continuing his brilliant second big-league season, Mark Prior scattered seven hits in 6 2/3 innings while fanning 10. Kyle Farnsworth and Joe Borowski nailed down the 4-2 victory as fans cheered when runs were put up on the center-field scoreboard for the spoiler Brewers against the Astros. The day’s drama climaxed in the nitecap as Sammy Sosa and Moises Alou homered while starter Matt Clement held off the Buccos in the 7-2 victory. That warmed the fans to fever-pitch in the 59-degree, cloudy twilight for the first Cubs’ division title since 1989. Once again the players toured the borders of the field to commune with the fans.

The team would continue its memorable ride through a five-game NLDS triumph – nailed down in Atlanta via a Kerry Wood masterpiece — and took a 3-1 lead on the Marlins in the NLCS. Then, all hell broke loose after a Prior pitch, Alou and a loyal Cubs fan came together in the most fateful incident in Cubs history. Five more years passed before another clinching at home.

2008 

The beautiful Sunday, Sept. 21, game against the Cardinals was more like a coronation that a drama-filled contest in which the postseason hinged on every pitch.

The Cubs, loaded with free agents OK’d by a Tribune Co. eager to sell the team, had cruised most of the season, reaching a high point of 35 games over .500 by the end of August. Much of the potential down-the-stretch worry had been solved with a stirring four-game sweep of the Brewers, their main competitor, at Miller Park at the end of July. So the tag end of a three-game series against their arch-rivals was completing a formality as the Cubs’ first-place lead widened in the final month.

More than 40,000 had a sense of self-satisfaction as manager Lou Piniella began setting up his playoff rotation by pulling starter Ryan Dempster after five innings in the 5-1 victory. The Cubs were 94-60, 10 games ahead, with the win. Fans poured into the streets around the ballpark afterward in celebration. The dominance of the powerful lineup and deep rotation was a welcome distraction from darkening economic news about a “financial collapse.”

The clincher proved to be the ’08 Cubs’ last hurrah. Somehow, the players lost their mojo in the next 10 days. They were swept by the Dodgers three in a row in the NLDS, looking jittery and nervous in the process. Pitchers second-guessed Piniella’s moves. The manager later admitted he should done more to take pressure off the latest group to challenge sports’ longest championship drought.

And now the baton is passed to the 2016 Cubs to prove yet another division clinching is just a prelude to much bigger and better things.

Read the current issue of the Cook County Chronicle

— A clincher at Wrigley, and Cub fans hope for bigger things this postseason –