PHOENIX -- The D-backs were mathematically eliminated from the postseason race on Monday night when they fell to the Cardinals, 9-7, at Chase Field.

But truly, their chances ended two weeks earlier.

• Box score

On Sept. 15, the D-backs led the Reds, 3-2, heading into the bottom of the eighth inning at Great American Ball Park. A win would have been the sixth straight for the D-backs and their 13th in a 14-game stretch.

More importantly, because the Cubs had lost, the D-backs would have pulled to within one-half game of the second National League Wild Card spot.

The Reds, though, tied the game in the eighth and walked off with a win in the ninth. The loss sent the D-backs into a spiral, as they were swept in a four-game set by the Mets in New York and then lost the following night at home to the Reds again.

That six-game losing streak doomed the D-backs’ playoff hopes.

“Yeah, the New York trip. If I’m going to look back at one series of games that was extremely pivotal, that would be it,” D-backs manager Torey Lovullo said. “We made a great run. It was the run that I had been waiting for all year long. We felt extremely good about where we were, and we just got stymied. I just think we left a little money out there on the table and a little bit of meat on that bone. We’ll figure out how to make that better for next year.”

Veteran shortstop Nick Ahmed also lamented the September losing streak.

“We were playing great,” he said. “But we ended up losing five or six in a row, I think, which killed us. We have to try to limit our streakiness next year, I guess, keep on the hot streaks but try to find a way to put a stop to the cold ones when they come a lot sooner.”

In fairness, the D-backs entered the 2019 season without All-Star first baseman Paul Goldschmidt, who was traded to the Cardinals in December and made his return on Monday, scoring a pair of runs and smacking a two-run homer -- his 100th at Chase Field.

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Then they lost lefty Patrick Corbin and outfielder A.J. Pollock to free agency.

Right-hander Luke Weaver, part of the return in the Goldschmidt trade, had a great start to the year before suffering an injury in late May that kept him out until last weekend.

Taijuan Walker suffered a setback in his return from Tommy John surgery and has not pitched this year, and outfielder David Peralta missed a large portion of the season due to a shoulder injury.

Even when the front office dealt ace Zack Greinke just prior to the Trade Deadline, the team found a way to hang around the .500 mark and in the NL Wild Card race.

“No one ever gave up,” said Ahmed, who hit his career-high 19th homer on Monday. “No one ever showed up and packed it in. It’s disappointing. You never want to play a season and not play in the postseason.”

When he took over as general manager prior to the 2017 season, Mike Hazen said he wanted to build a sustainable winner.

Rather than break apart a team that finished a dismal 69-93 in 2016, he kept the core together and made changes at the margins. That resulted in an NL Wild Card berth in 2017 and an '18 season that saw the D-backs lead the NL West on the first day of every month before a September swoon kept them out of the postseason.

Hazen again chose to try to balance building for the future with competing in 2019, and by that measure, the season was a huge success.

With a slew of early picks in the 2019 MLB Draft, the D-backs injected talent into the farm system, and the trades of Greinke and Goldschmidt helped at the Major League and Minor League levels and gave the team some financial flexibility.

Hazen, though, isn’t about to take a victory lap.

“Wherever we finish this season, it’s going to be, plus or minus, around .500, and it’s not going to be good enough to get into the playoffs,” Hazen said. “To me, that’s not what we’re shooting for. We need to improve that. We need to increase our level of competition. We need to increase our level of production, including me, across our organization.”