Telemundo is celebrating a strong summer performance in primetime that has allowed the Spanish-language network to pull ahead of the long-dominant Univision in the adults 18-34 demographic for the first time.

NBCUniversal-owned Telemundo has been steadily chopping away at Univision’s lead in the Spanish-language TV arena for the past few years. Under the Comcast regime, NBCUniversal has poured resources into Telemundo. NBCU chief Steve Burke has frequently cited Telemundo and its related Spanish-language businesses as ripe growth opportunities for the Peacock.

In the 2010-11 season, Univision averaged 2.2 million viewers in the adults 18-49 demographic in the Monday-Friday primetime frame, compared to 685,000 for Telemundo. By 2014-15 that gap had narrowed considerably (Univision’s 1.3 million to Telemundo’s 802,000). For the 2016-17 season to date, the margin between the rivals is razor-thin (Univision’s 822,000 to Telemundo’s 790,000). In adults 18-34, Telemundo has a 2% edge for the season to date.

Telemundo’s summer slate has added to its momentum. The returning drama series “El Senor de los Cielos” and new novelas such include “Mariposa de Barrio” and “Sin Senos si hay Paraiso” have kept viewership strong this summer.

For the past four weeks, Telemundo has enjoyed a 30% advantage over Univision in the adults 18-49 demo in Monday-Friday primetime (Telemundo’s 894,000 to 688,000). Univision maintains a 20%-25% advantage in total viewers. Telemundo has also outrated Fox and CW in adults 18-49 for some weeks this summer.

Telemundo has been No. 1 in adults 18-34 among Spanish-language networks for the past six weeks, drawing 391,000 viewers to Univision’s 297,000. Among both networks, the bulk of viewership remains live or within 24 hours of a program’s premiere — in contrast to the English-language networks that are grappling with the migration of audiences to delayed-viewing platforms.

Univision notes that it has a few big guns ready to roll in the fall, including the premieres next month of the second season of the crime thriller “El Chapo” (a co-production with Netflix) and the return of dance competition series “Mira Quien Baila.”

Industry observers say the heightened competition between Telemundo and Univision has been good for the market overall. Both networks are investing more in a wider variety of programming. The two occasionally duke it out over turf, such as the dueling biopic series on Latin music superstar Luis Miguel that both are preparing.

Telemundo’s gains indicate that its strategy of targeting bilingual and U.S.-born Hispanics with programs largely produced in the U.S. and infused with multicultural sensibilities is resonating with viewers. Telemundo is expected to get another boost next year when it adds soccer’s World Cup games to its lineup for the first time.

(Pictured: “El Senor de los Cielos”)