But that’s no matter to Audi. The German marque, which has sexy pretty well covered by other models in its expansive lineup, has made long-haul range the top-line message for the new A3 TDI sedan. And indeed, this is a car that makes the most of its 13.2 gallons of fuel. During a recent Audi-sponsored event called the TDI Challenge, a caravan of motoring journalists in A3 TDIs logged more than 800 miles on a single tank of diesel, driving between the US cities of Albuquerque, New Mexico, and San Diego, California.

But a week spent in the company of a mid-level A3 2.0 TDI revealed that there is a good deal more to love about Audi’s value leader than bladder-bursting endurance. On the road, the car feels not unlike Volkswagen’s very fine Golf TDI, which should come as no great surprise as both share the VW Group’s stiff MQB platform. But despite the architectural similarity to its lesser cousin, the A3 comes off as a full-blooded Audi – quieter, more refined and, thanks to a raft of techno-upgrades, considerably more sophisticated. The A3’s available 4G LTE connectivity headlines its technology story; the faster connection makes Audi’s Google Earth-enabled navigation system all the more astonishing.

Front-wheel drive is, for an Audi in the US, a novelty, but it is key to the A3 TDI’s frugality. Official fuel economy ratings of 36mpg in the city and 43mpg on the highway are conservative; with a light touch on throttle and brakes, our test car’s instant fuel-economy display more than once reported 50mpg on the open road. (And some of the cars in Audi’s TDI Challenge yielded better than 60mpg.)

These impressive returns highlight the folly in American customers’ fixation with four-wheel drive. And yet, there are signs of change. In 2013, some 93% of the cars Audi sold in the US were equipped with Quattro all-wheel drive (compared with 44% globally). In 2014, that figure was down to 89% – a decrease attributable to the arrival and rousing success of the A3 sedan and cabriolet models, all but the top trim levels of which offer only front-wheel-drive.

As Mercedes-Benz did at the debut of its small CLA four-door, Audi touts an oh-so-accessible $29,900 base price for the A3 sedan – $30,795 with destination charge. For that sum, a buyer gets a 170-horsepower 1.8-litre turbocharged four-cylinder gasoline engine (a 220hp 2-litre four is optional), a six-speed automatic transmission and leather seats. The tested turbodiesel model, in well-optioned Premium Plus dress, cracked the $40,000 mark. And buyers who move up to the 292hp S3 could spend more than $50,000. That’s a fairly broad spread for an entry-level model, but there’s little question the A3 and S3 will be doing some heavy lifting for Audi in the US and around the world. The company sold 2,383 A3s in the US during January, putting it a close second to the top-selling Q5 crossover.

While Mercedes’ high-style CLA sedan comes off as little more than tool for winning the hearts of younger buyers, the A3 feels like something greater, a lovingly crafted homage to a well-remembered model – the 1995 A4 sedan. That the new A3 happens to be the most affordable Audi seems beside the point; the car, like BMW’s 2 Series coupe, is a complete thought, a legitimate family member whose stand-alone goodness belies its modest staring price.

And although it is difficult to discount the naughty appeal of the S3, it seems that Audi's small sedan is at its very best with the turbodiesel engine. The car – particularly one equipped with an goodly assortment of electronic mod cons – is proof that hybrid-level fuel economy need not come at the expense of motoring pleasure, and that motoring pleasure need not be the exclusive domain of the big spender.

If you would like to comment on this or anything else you have seen on BBC Autos, head over to our Facebook page or message us on Twitter.