* Third-quarter profit up 8 pct to C$0.75/share
* Revenue C$825.4 mln vs estimate C$824.5 mln
* U.S. same-store sales rose by 3 pct
Nov 7 (Reuters) - Canadian coffee and doughnut chain Tim Hortons Inc reported an 8 percent rise in quarterly profit as same-store sales improved slightly in the United States.
The company, which says it sells eight of every 10 cups of coffee sold in Canada, said U.S. same-store sales rose by 3 percent, while same-store sales in Canada increased 1.7 percent.
Tims opened 13 restaurants in the United States and 34 in Canada during the quarter.
The coffee shop chain, which is facing intense competition from U.S. competitors such as McDonald's Corp and Starbucks Corp, is also under pressure from shareholders to boost returns.
The company, led since July 2 by long-time Nestle SA executive Marc Caira, said in August it would expand its buyback plan by C$900 million to C$1 billion.
Last week, Tim Hortons said it would start offering a dark roast coffee option, the first time in its nearly 50-year history that it has offered customers a new blend of coffee.
The company's net income rose to C$113.9 million ($109.4 million), or 75 Canadian cents per share, in the third quarter ended Sept. 29 from C$105.7 million, or 68 Canadian cents per share, a year earlier.
Total revenue rose 3 percent to C$825.4 million.
Analysts had expected a profit of 77 cents per share and revenue of $824.5 million, according to Thomson Reuters I/B/E/S.
Tim Hortons' shares listed on the Toronto Stock Exchange have risen 22 percent this year.