McDonald's Corp. (MCD) Wednesday said worldwide sales at its namesake restaurants open at least 13 months rose 3.9 percent in August as stronger-than-expected returns in the U.S. market helped offset weak sales in Europe.

The world's largest fast-food chain said same-store sales, a key measure of retail performance, rose 7.2 percent in the United States, its largest market, thanks to strong sales of new menu items like its Chicken Selects (search) fried chicken strips.

Restaurant analyst Larry Miller of Prudential Securities had been expecting a rise of 4 to 5 percent in U.S. oe of J.P. Morgan had forecast a gain of between 2 and 3 percent.

Same-store sales fell 0.9 percent in Europe, the company's No. 2 market, due to weak performance in Germany, poor weather and a decline in tourism.

Both Miller and Ivankoe had predicted flat same-store sales for the company's European business.

McDonald's said same-store sales in the Asia-Pacific, Middle East and African regions rose 0.9 percent.

In a note to clients, Miller said McDonald's' U.S. results were strong enough to offset the weakness in Europe and Asia.

"If Euorpean sales reaccelerate, they could act as a catalyst for McDonald's shares," Miller wrote. "This would most likely come from the initiatives in place and any improvement in the European economic outlook."

Total sales rose 8.6 percent, helped by the weaker dollar, which raises the dollar value of sales overseas.

Sales in Europe rose 11 percent, but were up only 0.6 percent in local currencies.

McDonald's shares were up 49 cents, or 1.8 percent, at $27.87 Wednesday on the New York Stock Exchange (search).