MEXICO CITY, Oct 21 (Reuters) - Grupo Televisa , Mexico's largest broadcaster, reported on Thursday a 77.3% drop in net profit in the third quarter compared with the same period a year earlier.

The company posted third-quarter net profit of 760.6 million pesos ($36.8 million) compared with 3.350 billion pesos in the same period last year, falling short of a Barclays estimate of 933 million pesos.

Televisa said its bottom line took a hit from the Mexican peso's 3.7% depreciation versus the U.S. dollar during the quarter.

Revenue grew 9.1% to 26.128 billion pesos, from 23.943 billion pesos in the year-earlier period. That was above a Barclays prediction of 24.5 billion pesos.

Televisa operates several television channels along with other media including a cable broadband and direct-to-home satellite pay television. In recent years it has been under pressure to meet the challenge of streaming services which have drawn away viewers.

However, advertising revenues jumped in the quarter, up 25% over the previous three month period, and 16% over the same period in 2020, led by a recovery in private sector advertising spending.

To battle rivals such as Netflix, Televisa and leading U.S. Spanish-language broadcaster Univision announced in April they would merge content through the creation of a new Spanish language media company, in which Televisa will be the largest shareholder.

The new firm, called Televisa Univision, will launch a global streaming platform with content from both.

Mexico's telecommunications regulator, IFT, last month authorized the tie-up. The transaction is expected to close this year, Televisa said.

In September, Televisa said the sale of its 40% stake in Ocesa Entertainment to U.S. firm Live Nation would move forward, a move that would support Televisa's deleveraging efforts, according to S&P Global Ratings. ($1= 20.642 pesos at end-September) (Reporting by Noe Torres and Anthony Esposito in Mexico City; Editing by Daina Beth Solomon, Matthew Lewis and Chris Reese)