UPDATE 1-PSA lifts revenue on Opel, although it loses more ground in China

* Raises market forecasts for Latin America, Russia

* But PSA loses ground in China

* Q3 revenues up 31 pct to 15 bln euros (Adds detail and background)

PARIS, Oct 25 (Reuters) - French carmaker PSA Group said quarterly revenue rose by almost a third, as the Peugeot maker added Opel-Vauxhall sales numbers for the first time while increasing deliveries in Europe and a rebounding Latin America.

PSA raised its 2017 market forecasts for Latin America and Russia but continued to lose ground in China, where the group's registrations plunged another 29 percent.

Group third quarter revenues rose 31 percent from a year ago to 15 billion euros ($17.6 billion). Automotive division revenue at its existing Peugeot, Citroen and DS brands rose by a more modest 11.6 percent to 8.42 billion euros.

Under Chief Executive Carlos Tavares, PSA has powered to record profitability but lost its footing in China, the world's biggest auto market, where deliveries topped 700,000 cars in 2014. Sales in the region - mainly through two Chinese joint ventures - stood at 242,000 vehicles for first nine months of the year.

PSA is now attempting to sell or lease out one of its five Chinese plants, French daily Les Echos reported on Wednesday, citing unnamed sources. The company declined to comment.

Sales at PSA's China ventures are not consolidated in its group revenue, which rose in the quarter on a healthy 3.9 percent increase in European deliveries - excluding Opel-Vauxhall - while Latin American registrations jumped 17 percent.

PSA raised its 2017 market growth outlook to 7 percent in Latin America and 8 percent in Russia, from a previous 5 percent forecast for both markets, echoing a similar upgrade by Renault this week which also posted higher sales.

New model launches improved the so-called mix, the company said, reflecting a demand to pricier vehicles and trims, which contributed a 5.4 percent revenue increase in the quarter.

Sales to partners delivered a further 3.7 percent boost as PSA began manufacturing two Opel vehicles under a deal predating its full acquisition of the General Motors brand.

($1 = 0.8505 euros) (Reporting by Laurence Frost; Editing by Sudip Kar-Gupta)