In September 2016, for the first time since October 2014, the Chevrolet Camaro outsold the Ford Mustang in the United States.

Year-over-year, Chevrolet Camaro sales jumped 25 percent to a five-year September high of 6,577.

With the worst Ford Mustang decline since (not coincidentally) October 2014, the Blue Oval's pony car saw its share of the three-car Detroit pony/muscle car sector fall by 15 points to 34 percent.

Thus, the Camaro wins. Over the span of one month. By a small margin.

In 2015, for the first time since 2009, the Mustang generated more U.S. sales than the Camaro. It wasn't an unexpected turn of events. In 2015, the Ford Mustang was an all-new sixth-generation car. The Camaro, on the other hand, was in the final year of its fifth iteration.

Camaro sales fell to a six-year low. Mustang sales rose to an eight-year high.

2016 Ford Mustang GT convertible

The expectation that 2016 would be a turnaround year for the Camaro apparently lacked foundation. With the Mustang no longer hot off the presses and the Camaro now the all-new car, year-over-year Camaro sales volume plunged 15 percent through the first two-thirds of 2016, a loss of 8,340 sales that General Motors largely laid at the feet of decreased fleet emphasis and a focus on stocking high-priced, high-performance examples for the Camaro enthusiast.

The sixth-gen Camaro's dynamic enhancements, however, were linked to a car that doesn't look new and continues to suffer from the sort of wretched visibility that decreases the car's daily driver appeal by the masses.

Even the Dodge Challenger, long a third wheel, began to outsell the Camaro on occasion.

With inventory on the departing 2016 models too strong, GM responded with a Camaro price cut. (GM currently offers interest-free financing over six years for most 2016 Camaros.) And then, as 2017 Camaros came on stream, GM also sliced away at the new model year's pricing scheme.

Camaro Mustang Challenger sales chart

The result of more attractive prices: the Chevrolet Camaro outsold the Ford Mustang by 148 units in September 2016. Though it was a tiny margin caused more by the Mustang's 32-percent dive than the Camaro's 25-percent increase, the Camaro's September victory still marks a sharp turnaround from the 4,210-unit margin of victory the Mustang scored at this stage of 2015.

Dodge Challenger sales rose 19 percent to 5,698 units, a four-month high and the best September result since the Challenger returned in 2008. Annually, Challenger sales have steadily increased ever since the nameplate was reborn, rising 80 percent between 2010 and 2015. But through three-quarters of 2016, the Challenger is off last year's pace by 2 percent.

As for the Mustang's harsh decline in September, Ford mostly blames the Mustang's success in 2015. Speaking about last year, Ford sales analyst Erich Merkle told TTAC, "We were satisfying a lot of pent-up demand, as buyers in this segment tend to wait for launch of the newest model."

Pointing to the Mustang's massive year-to-date sales lead - Ford sold 60-percent more Mustangs than Chevrolet sold Camaros in the first nine months of 2016 - Merkle also noted recent price alterations. In September, Merkle says, "We also saw a healthy increase in incentive activity for the overall segment," claiming that Mustang incentives decreased by $250 compared with August while the sector's average incentives were up $600 compared with the previous month.

With the newer car priced appropriately, it seems the Chevrolet Camaro can beat the slightly older Ford Mustang. But after 22 months of Mustang leadership, was this surprising Camaro victory just a blip on Ford's radar?