* Mazda Q3 profit falls, hit by rouble slide, product mix
* Fuji Heavy ups FY op profit view, U.S. sales strong (Recasts throughout with Mazda results)
By Chang-Ran Kim and Maki Shiraki
TOKYO, Feb 4 (Reuters) - Japan's Mazda Motor Corp said the rouble's plunge bit into European revenue and kept annual profit targets unchanged, while Fuji Heavy Industries Ltd , home of the Subaru, raised forecasts on brisk U.S. auto sales and a weaker yen.
Both of the second-tier automakers benefit from a weaker Japanese currency because they export most of the vehicles they produce at home. But Mazda said the yen's weakness against the dollar was outweighed by a worse-than-expected impact from the Russian currency's collapse, cutting its third-quarter earnings.
Mazda on Wednesday posted a 5.2 percent drop in October-December operating profit to 48.0 billion yen ($409 million), below an average analyst estimate of 53.5 billion yen. Its new Mazda2 hatchback sold well, it said, but brings lower per-vehicle profits than bigger models like the Mazda6 or CX-5.
The Hiroshima-based firm said it still expects annual operating profit of 210 billion yen, up 15 percent from the previous year.
Outgunned in scale by giants like Toyota Motor Corp and Nissan Motor Co, both Mazda and Fuji Heavy have been focusing on differentiating their products to lure customers - Tokyo-based Fuji Heavy with its all-wheel-drive Subarus, and Mazda with sporty yet fuel-efficient models. That has helped Subaru boost sales in the United States, while Mazda has won over drivers in Europe.
Subaru has struggled to keep up with U.S. demand for years, keeping inventory and sales incentives low.
That factor has helped counter tepid sales in China and the impact of a shrinking domestic market: Fuji Heavy lowered its full-year vehicle sales projections a fraction to 903,000, with stronger-than-expected sales in North America offsetting weakness in almost every other region.
Fuji Heavy said it now expects operating profit of 410 billion yen for the year through March, up more than 7 percent from a previous forecast of 382 billion yen.
In the third quarter, operating profit soared 51 percent to 124.49 billion yen, handily beating an average estimate of 109.7 billion yen in a poll of 10 analysts by Thomson Reuters I/B/E/S.
Fuji Heavy also changed its yen-dollar exchange rate assumption, to 108 yen from 104 yen. The weaker yen provides a tailwind for the company since each sale in dollars translates into more of the Japanese currency.
Its heavy currency exposure and popularity in the United States have made Subaru one of the most profitable automakers in the world, with its operating profit margin seen at 14.4 percent for the current fiscal year.
($1 = 117.3800 yen) (Editing by Kenneth Maxwell)