BILLINGS -- White House hopeful Barack Obama telephoned his defeated primary rival Hillary Clinton late Tuesday to thank her after she gave an "outstanding" appeal for Democratic unity, aides said.

"I thought she was outstanding," the Illinois senator said after watching Clinton's convention speech in Denver at the home of local supporters here.

"That was excellent, that was a strong speech. She made the case for why we're going to be unified in November and why we're going to win this election," he said, according to a pool report.

After leaving the house party, Obama called and talked for several minutes with Clinton to say "how grateful he was for her support, that she gave a terrific speech," his communications director Robert Gibbs said.

Obama also said "he loved her line 'No way, no how, no McCain,'" he said, referring to Republican rival John McCain.

"Senator Obama also called and spoke with president Bill Clinton for several minutes saying Senator Clinton could not have been better and made the case for change," Gibbs added.

"Obama said he knew how proud he must have been watching as he was last night watching [his wife] Michelle speak and how grateful he was for their support."

Watching the speech intently in the small living room of his host family, Obama had responded appreciatively as Clinton went through the reasons why her supporters should rally behind him and against McCain.

When she said she was "a proud supporter of Barack Obama" he smiled and said "yay." He clapped when she said "no way, no how, no McCain."

He nodded solemnly as Clinton demanded of her supporters whether they had backed her, or backed sick veterans, single mothers and others in need, and clapped when she praised Michelle Obama.

Obama said a video put together by the Clinton camp, lauding her unsuccessful bid to secure the Democratic nomination, was "great" and praised Chelsea Clinton as a "wonderful young woman" when she introduced her mother.

Obama is due to arrive in Denver on Wednesday before giving his acceptance address as the first African-American nominee of a major party the next day.