Honda has made a quick U-turn. Just 19 months after its Civic compact hit showrooms and was slammed by critics, the company has revamped the car, giving it a sportier look and upgrading the interior.

It’s an unusual and costly do-over. But Honda – among the industry’s most highly-regarded brands – was worried the car’s flaws would hurt sales and market share, analysts say.

The 2013 version went on sale Thursday. Honda has given it a sportier profile, replaced its chintzy dashboard and made the ride quieter. The revamp came to market in about half the time it normally takes, showing how concerned Honda is about falling behind.

“The new consumer coming to the marketplace looking for a compact car doesn’t think the Civic is a slam-dunk anymore,” said Jesse Toprak, vice president of market intelligence for the auto pricing website.

The company misjudged the small-car market when it rolled out the Civic in April of last year, analysts say. Small-car buyers used to tolerate cheap materials, noisy interiors and boxy styling just to get high gas mileage. But they now expect their gas-sippers to have a quiet ride, crisp handling and plush seating. The 2012 Civic lacked those refinements. It was so noisy that “I kept trying to put the windows up,” recalled IHS Automotive analyst Rebecca Lindland, who said the competition caught Honda off-guard.

But criticism of the 2012 Civic hasn’t dented demand. Sales of the car have risen to 255,000 through October, up 39 percent from last year. The car has passed the aging Toyota Corolla and the Chevrolet Cruze to become the nation’s top-selling compact.

The increase came mainly because Civics were in short supply last year following an earthquake in Japan. Loyal customers delayed purchases until the Civic returned, Toprak said. The Civic also is selling well because of discounts, he said. Dealers are knocking about $2,500 off the sticker price to clear out 2012 models..

Company executives get prickly when asked if criticism was why they moved so fast to update the Civic. They say only that they wanted to keep the car ahead of the competition.

Honda added insulation to cut engine noise, put in thicker glass to reduce wind and made the brakes larger to stop the car faster. The seat material was upgraded, and Honda added a softer dashboard with two colors. Outside, the car got it a more aerodynamic look with a new hood, trunk lid and lights.