There’s a real dogfight shaping up among the top three luxury car makers in the final three months of 2010. Lexus, which has traditionally been the best-selling luxury brand in the United States, is trying hard to hold off a resurgent Mercedes-Benz and BMW.

The companies are currently neck-and-neck in sales through September, with Mercedes leading at 165,363 vehicles, compared to 163,184 for Lexus and 157,464 for BMW, Forbes reported.

“These next three months, including the luxury holiday sales campaign, are crucial for Lexus if they want to continue to lead the market as they have for over a decade,” said Jesse Toprak, vice president of industry trends and insight at TrueCar.com.

Lexus’ lost momentum can be traced to some of the same quality issues that have hurt its sister brand, Toyota, and to the fact that it hasn’t had much in the way of new models to lure shoppers to showrooms. The GX460, a relatively low-volume SUV, debuted in early 2010. The next new model is the CT200h, a dedicated hybrid, which is coming to market around the first of the year.

Smelling blood, Mercedes has been offering aggressive lease deals on its vehicles. It has also benefited from new products, like the GLK, a small SUV, and a new generation E-class sedan. After a slow year in 2009, BMW is also beginning to pick up steam with a redesigned 5-series sedan. Next year it hopes to build on that momentum with the introduction of the X1 small SUV and a redesigned X3 SUV.

Lexus will have to work hard to hold off its German rivals.