The A3 has been a sales staple for Audi. It made the Four Rings more accessible, without compromising the brand’s hard-earned reputation for class and quality. It also pioneered the premium compact hatchback segment, and gave the marque a car park presence that, at least at first, could not be emulated by the likes of Mercedes-Benz and BMW.

Now in its third generation, the latest A3 is also Audi’s finest yet, thanks in part to a class-leading chassis (shared with the VW Golf 7) that finds that elusive sweet spot between smooth composure and involving dynamics

Add the finely honed interior (which, although aesthetically minimalist in execution, is both well equipped and tactilely satisfying) and it’s easy to understand why the latest A3, in three-door hatchback and five-door Sportback form, continues to attract strong sales support.

But there’s another factor to consider here. Buying down has become a car purchasing reality, and not only at the budget end of the market. Increasingly, sophisticated buyers are demanding smaller, more efficient cars – as long as they don’t skimp on comfort and convenience.

So, while premium compact sedans like the Mercedes-Benz C-class, the BMW 3-Series and Audi’s A4 have always accounted for the mainstream volumes of their respective brands, the real growth potential is shifting to smaller form factors.

With hatchbacks already part of the product portfolio, it didn’t require rocket science to that Audi’s next salvo in the battle for small smart car supremacy would be a booted version of the A3. The A3 Sedan, which officially arrived in South Africa this week, could well become the strongest seller in the line-up.

Part of the reason is that the A3 Sedan is not just a hatchback with a boot. It’s very much its own car – a meticulously engineered four-door sedan that benefits from the legacy of the A3 platform, but also manages to interpret its virtues in a different context.

Admittedly, that may not be all that obvious at first. The strong identity that Audi has nurtured so carefully over the years means that the new four-door is instantly recognisable, but not necessarily as an A3 Sedan.

From a distance, without the benefit of scale or direct comparison, it’s easily mistaken for an A4, if only because the combination of that prominent single-frame grille, the four doors and a boot tend to suggest it.

However, to consider the A3 Sedan little more than a smaller A4 doesn’t do the newcomer justice. Up close, you immediately notice how different the smaller sedan’s proportions are.

Compared to an A3 Sportback, the sedan is markedly longer, but also slightly wider and lower, emphasising a stance that is poised and athletic. The boot line flows neatly from the C-pillar into short, high deck that adds further visual muscle.

The more compact design also brings other Audi design trademarks into sharper focus, including the high, sharp-creased waistline, the narrow glass aperture, the steeply raked windscreen and the tapered headlights – the latter outlined by the now obligatory daytime running lights.

Park it next to an A4, and you’ll see how much more compact the A3 Sedan is. And while the A4 has always been a handsome car, its younger sibling looks the sportier part, thanks to is stockier, more aggressive road presence.

It’s a car that benefits from the modern-day obsession with bigger wheels and lower-profile rubber: standard 17-inch rims look barely adequate, and the 18-inch options are likely to be a popular add-on.

The powerful visual appeal of the A3 Sedan creates equally lofty expectations on the dynamic front, further fuelled by the knowledge that it’s anchored to the same, modular platform as its hatchback stablemates.

I’m not going to delve into the technical details here, but it’s a chassis that, in its hatchback application, finds an impressive compromise between compliancy and response, thus allowing ride refinement and crisp road manners to find satisfying common ground.

The good news is that the A3 Sedan continues that legacy, if not in quite the same way as the hatchbacks. Those slightly different proportions, together with about 35 kg more weight and a suspension tweaked accordingly, create an on-road character that is both instantly familiar, and unexpectedly different.

There’s a greater focus on refinement, with damper settings that are a smidgen more forgiving than on the Sportback, but without blunting the overall driving experience. If anything, the sedan feels more settled but on secondary roads, while still lucidly communicating its intentions.

No, I’m not saying that the A3 sedan feels stodgy or old-fashioned. Chassis feedback remains candid, and the steering is still pleasingly precise, even if the assistance can feel overdone at low speeds – good enough reason to drive with some intent.

And yes, as is also the case with the hatchback A3s, the Sedan rewards enthusiasm with real grip and composure, linked to a neutrality under hard cornering that still takes me by surprise – traditional, nose-ploughing understeer is not in the A3’s dynamic vocabulary, and that goes for the sedan version, too.

The A3 Sedan comes in several engine flavours, all of them turbocharged. Entry level is the 1.4 TFSI petrol engine, rated at 92kW in this application, and combined with 200Nm of torque.

Staying with petrol, the 1.8 TFSI links 132kW of urge to a 250Nm torque peak. And then, for diesel fans, the sedan can also be ordered with the 110kW/340Nm 2.0-litre TDI mill – a powerplant unique to the sedan in the A3 line-up.

There are just two transmissions to choose from: a traditional six-speed manual gearbox, and a seven-speed dual-clutch design, complete with shift paddles behind the steering wheel.

I drove all three versions of the A3 Sedan, two with manual gearboxes, and even the so-called entry-level 1.4 TFSI felt lively on the move, with the little turbo motor showing off impressive shove. It always feels like a bigger engine than it actually is.

Admittedly, a full load of occupants and luggage is likely to slow things down somewhat, but even so, the Sedan always feels stronger than its humble engine displacement suggests.

The 1.8 TFSI makes good use of its extra muscle to improve top-gear cruising over hilly terrain, and its higher sustained speeds also provide a better opportunity for the chassis’ talents to be explored.

The test car wore 18-inch wheels, which certainly benefited steering feel (and also looked great), but undermined some of the chassis’ suppleness. It felt more racy and more confident, partly due to the extra grip from the fatter rubber, but at the expense of refinement, including higher road noise levels.

The latest 2.0 TDI turbodiesel revs more effortlessly and sounds less gruff than expected for an oil burner – and it has a real appetite for long-distance cruising. Superior midrange punch means flooring it in almost any gear will result in resolute acceleration. It will also be the line-up’s economy king, especially for high milers.

Fuel consumption figures are predictably keen across the range, although the stats tend to be much more optimistic than any real-world experience. So, even though the TDI’s combined cycle thirst is supposed to be in the low 4 litres/100km bracket, expect high or even sixes in real-world, traffic-congested conditions.

Ironically, it’s the 1,4-litre engine that’s likely to be the thirstiest, mainly because it has to work a little harder to deliver its zip. But it’s also the most fun to drive, with the chassis and suspension allowing the little motor to be pedalled along as fast as it will go.

None of these A3 sedans is super-quick (we will have to wait for the S3 Sedan to arrive for that), but performance is certainly brisk enough to ensure entertaining dynamics.

Predictably, much of the A3 Sportback’s interior is carried over as is: clean, almost minimalist switchgear, superior materials, high tactile values, and ergonomically sound design. All sedans feature the comprehensive SE trim spec, but there is also an extensive list of optional extras.

The rear bench seat will accommodate two in comfort, and can also be folded flat to boost cargo space. That should only rarely be necessary, however, as the A3 Sedan features an adequate 425-litre boot that’s nice and deep.

Audi South Africa has positioned the A3 Sedan at the top of the A3 family, with pricing around R10k more than a comparable A3 Sportback. The marque will be hoping to attract new customers with the four-door, but it’s also likely to draw the attention of buyers who, up to now, have had to settle for the Sportback, or the larger A4.

The sedan now gives Audi a rival to the recently launched Mercedes-Benz CLA, suggesting that these small premium sedans are likely to become an increasingly frequent sight on local roads.

With the S3 Sedan not too far off, and more engines in the pipeline, the A3 Sedan could well become the brand’s sales success story for 2014. What will be really interesting is to see just where those sales were poached from… DM