After running neck-and-neck with Yoplait, Dannon has sprinted past its rival to lead the yogurt category -- estimated by Packaged Facts at $7.3 billion -- thanks to a new strategy in the fast-growing Greek segment.

Dannon now controls 27.8% of yogurt sales, compared with 25.8% for General Mills' Yoplait, according to the latest data from SymphonyIRI covering the year-to-date period ending March 31. The two brands were tied as recently as the end of last year at 27.1% share. At the end of 2011, Yoplait had a 31.6% to 26.7% lead. "Our leadership is not only sustainable, but the gap vs. the second player is increasing significantly," said Sergio Fuster, Dannon's chief marketing officer.

The newfound confidence marks a shift in tone for Dannon, which along with Yoplait had been outmaneuvered in the last couple years by Chobani, whose Greek-style blends surged out of the gate. Chobani remains a major player with 16.4% total yogurt share.

Dannon and Yoplait underestimated the speed and size of the Greek phenomenon. But Dannon appears to have regained footing faster. Rather than pushing a single variety of the thicker, protein-packed style, the marketer has introduced Greek versions across its lineup. "We do not see Greek yogurt as a segment," Mr. Fuster said. Rather, "we see it as a new platform over which we can position our segmentation strategy."

The Dannon "Oikos Greek" brand is positioned for "pleasure and taste," while the 80-calorie Light & Fit Greek is geared for weight management.  A new campaign urges women to "stop sacrificing," suggesting that you can get creamy taste without the calories. Activia Greek was recently relaunched with a creamier formula and new branding that makes "Greek" more prominent. A new ad shows spokeswoman Jamie Lee Curtis admitting to an "affair" with other Greek brands until she discovered the new Activia blend.

General Mills is pouring major support behind its Yoplait Greek 100-calorie yogurt and has made inroads. The brand also sells regular Yoplait Greek and Yoplait Greek with granola. But Yoplait's total yogurt sales slid 8.2% in 2012, compared with Dannon's 9% growth, according to SymphonyIRI. General Mills declined to comment. Dannon's agency is Young & Rubicam while Yoplait uses Saatchi & Saatchi.

Dannon's Oikos is benefitting from an "authentic positioning," while Yoplait "has the challenge of being more associated with kids and mainstream yogurt segment," said Rick Shea, owner of Shea Marketing.