Google chief executive Eric Schmidt on Friday said that Microsoft's Bing search engine was the company's main threat, not Facebook or Apple.
"While it's true Web search is not the only game in town, searching information is what it is all about," Schmidt said in Wall Street Journal interview video posted online.
He described Apple as a well-respected competitor and Facebook as a "company of consequence doing an excellent job in social networking," but said that Microsoft's latest-generation search engine was Google's main competition.
"We consider neither to be a competitive threat," Schmidt said, referring to Facebook and Apple. "Absolutely, our competitor is Bing. Bing is a well-run, highly competitive search engine."
Microsoft's Bing and other Internet search services overtook Yahoo! for the first time to become the number two search engine in the United States in August, according to The Nielsen Co.
Microsoft's Bing, MSN and Windows Live had a 13.9 percent share of US search volume in August, up 0.25 percent from July, while Yahoo! had a 13.1 percent share of US Internet searches, down from 14.6 percent in July, Nielsen said.
Google continued to dominate the lucrative search and advertising market with a 65.1 percent of all Internet searches in August, Nielsen said.
Year-over-year, Microsoft sites have increased their search share from 10.7 percent in August 2009 to 13.9 percent in August 2010 while Yahoo! has fallen from 16.0 percent a year ago to its current 13.1 percent, Nielsen said.
Google held steady at 65 percent.
Yahoo! and Microsoft forged a Web search and advertising partnership a year ago that set the stage for a joint offensive against Google.
Under the agreement, Yahoo! will use Microsoft's search engine on its own sites while providing the exclusive global sales force for premium advertisers.
Microsoft last month began handling all Yahoo! online searches in Canada and the United States and will eventually power Internet searches at Yahoo! websites worldwide.
Google both competes and partners with Apple, the maker of iPhones, iPods, iPads, and Macintosh computers, according to Schmidt.
Schmidt resigned from the Apple board as Google weighed into the smartphone arena with devices running on its open-source Android mobile software.
He said in a Charlie Rose interviewed published in Business Week that a deal to have Google as the default search engine on iPhones was renewed and that the Internet firm provides mapping and other services for Apple gadgets.
Schmidt said that Apple and Google are "two companies I care a lot about" and will remain close. He also said that Google could be improved by making features more social while providing users tools to manage their privacy.