Buick unveiled an all-new Buick Regal Tuesday as the once-sleepy brand continued its surge back to relevance in the U.S. premium market.

Based on the stunning Opel Insignia that debuted at the Geneva Auto Show in March, the Regal Sportback sedan boasts an innovative, roomy Tesla Model S-like hatchback. For customers who want even more rear utility, the Regal will also be available in a five-door wagon trim just like its European counterpart. Called the Regal TourX, the five-door is crossover-inspired, all-wheel drive variant will go head-to-head with the fashionable Volvo Cross Country or Audi’s Allroad.

Though Buick isn’t releasing pricing yet, it will likely be thousands of dollars less than those European competitors. Both the Sportback and TourX will be available in the fourth quarter of this year.

Buick has gotten its mojo back by presciently reading U.S. demand for crossovers. With a full SUV lineup – including the wildly popular, segment-first subcompact Encore – Buick is on a roll. Its three crossovers and three sedans are the most modern lineup in the industry, all having come to market in the last 21 months.

The entry-lux Regal enters the market at a time when sedan sales are tanking. Regal sales last year gained just 1.7 percent compared to the Encore’s 16.3 percent, for example. The Regal’s sister sedan, the larger Lacrosse, saw sales plummet 34.4 percent despite introducing an all-new vehicle.

But sedans remain the style leaders for car brands and the much-anticipated Regal is a head-tuner.

“You have to get noticed to stand out, and this car’s hallmark is its sculpted beauty,” said GM Vice President for Product Development Mark Reuss.

Based on GM’s new, front-wheel-drive Epsilon architecture which undergirds the new, roomy Chevy Malibu, the Regal is considerably larger than the last generation with a three-inch-longer wheelbase that translates into almost that much more room in the rear seat. The sedan will come standard with front-wheel drive, with all-wheel drive available as an option as on the current Regal. Expect a high performance version to come later.

The 2018 Regal has a new turbocharged mill under the hood, scrapping the old model’s normally aspirated, base 2.4-liter engine. A 2-liter turbocharged four-cylinder engine will power both the Regal Sportback and TourX space and will be mated to GM’s new nine-speed automatic transmission. The same engine that powers the Chevy Malibu, it will pump out considerably more muscle with 250 horsepower and a whopping 293 pound-feet of torque in the TourX. The TourX will also feature a cavernous 73.5 cubic feet of storage.

The Regal was designed in Germany by Opel, which GM recently sold to PSA Group, owner of Renault and Citroen.

Henry Payne is auto critic for The Detroit News. Find him at hpayne@detroitnews.com or Twitter @HenryEPayne.