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Audi released this "teaser' photo of its E-Tron GT, a Tesla-fighting four-door that it plans to launch in 2020. Audi AG

This article originally appeared in the Motley Fool.

German luxury-car maker Audi AG (NASDAQOTH:AUDVF) threw down a big gauntlet this past week: It showed a photo of an upcoming electric luxury sedan that is very clearly aimed at Tesla's (NASDAQ:TSLA) groundbreaking Model S.

The Audi e-tron GT is likely to be the third Tesla-like vehicle from the German luxury brand, following an SUV and a sporty crossover. We don't know too much about it yet. But if you had any lingering doubt that Audi's electric-vehicle effort is aiming squarely at the Silicon Valley upstart, this photo should erase them.

Here's what we know about Audi's Tesla-fighting effort so far.

Audi's E-Tron GT Is Aimed Right At The Model S

While Audi CEO Rupert Stadler said in 2016 that his company had a Model S-fighter in the works, almost everything we know about the Audi e-tron GT so far is contained in this tweet from Audi Sport from this past Thursday.

If ever a picture was worth a thousand words, the darkened photo of the prototype e-tron GT is one. It's a four-door with a profile and roofline strongly reminiscent of classic two-door grand touring cars from companies like Aston Martin and Maserati -- a timeless shape, but fully up to date.

Of course, that also aptly describes the shape of Tesla's Model S, making it clear where the e-tron GT will be aimed when it arrives in two years -- as the third in a new line of Tesla-fighting electric Audis.

Extensive Pre-Production Testing Of Audi's First Battery-Electric

First up in Audi's Tesla challenge is a production version of the electric luxury SUV that Audi first showed in 2015. A lightly camouflaged near-final version, which Audi is now calling the e-tron, appeared at the Geneva Motor Show earlier this month.

Back in 2015, Audi said that the e-tron will have a three-motor configuration, one in front and two driving the rear wheels, with a 95 kilowatt-hour (kWh) battery providing a claimed range of "over 500 kilometers". (Expect a rated range of around 280 miles on the strict U.S. EPA test cycle.)

More recently, Audi has said that the production version can be recharged in just under 30 minutes with a 150-kilowatt DC fast charger. (Audi uses the Combined Charging Standard, or CCS, which allows for slow AC or fast DC charging.)

In a clear jab at Tesla, which conducts only very limited pre-production testing, Audi said that its fleet of pre-production e-trons has already racked up over 3 million miles in testing, in temperatures ranging from below minus-20 degrees Celsius to above 50 degrees Celsius (minus-4 to 122 degrees Fahrenheit). Audi emphasized that it's also conducting extensive tests of its recharging technology in conditions around the world.

The takeaway: The production e-tron, which might be called the Q6 when it arrives, should be very reliable when it launches in Europe late this year. It will arrive in other global markets, including the U.S., in the first half of 2019.

A Slew Of Plug-In Audis On The Way

The e-tron SUV will probably be followed in 2019 by a production version of the e-tron Sportback concept shown last year. It's a sporty compact crossover SUV that, at least in show-car form, shared the e-tron SUV's drivetrain and battery pack. That in turn, we now know, will be followed by the e-tron GT in 2020.

Beyond that? Stadler has promised "more than 20 electric cars and plug-in hybrids by 2025", part of corporate parent Volkswagen AG 's (NASDAQOTH:VLKAY) massive (and massively funded) push to launch a slew of battery-electric and hybrid vehicles across its brands.

I suspect that the e-tron's launch and early build quality, to say nothing of its interior, will prove to be a stark contrast to Tesla's experience to date, which has been marked by months-long production ramp-ups, poor panel fits, and early reliability issues. It could be a sobering experience for fans of -- and investors in -- the upstart Silicon Valley automaker.

John Rosevear has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Tesla. The Motley Fool has a disclosure policy.