"This is a tough presidential campaign we're in," McCain said. "I have a very honorable opponent. There are stark differences between us."
In recent speeches, McCain has criticized Obama as not ready to be president and as a candidate who is willing to lose the war in Iraq to win the campaign. When Obama charged that McCain was questioning his patriotism, McCain responded that he was only questioning Obama's judgment.
Seeking at least a slice of media attention amid the Democratic National Convention, McCain visited the Phoenix high school where his wife, Cindy, graduated.
"I know you have students who come from all over the world. I know there are people here who come from countries, some from Iraq where they have seen the look of war and sacrifice," he said.
McCain, who turns 72 on Friday, got a generational boost from Daddy Yankee, a Puerto Rican star of reggaeton, a mix of reggae, rap and Latin music styles. Students squealed with delight as Yankee appeared and endorsed McCain.
"I believe in his ideals and his proposals," Yankee said. "He's been a fighter for the Hispanic community. He's been a fighter for the immigration issue."
McCain was scheduled to travel to California to raise money and make an appearance on NBC's "Tonight" show before returning to Phoenix late Monday.
McCain was out of the public eye on Sunday, going to church and a baseball game before a one-hour private meeting at a Phoenix hotel, which aides described as private. They declined to identify those attending. That fueled speculation about McCain's selection of a running mate, a decision he's scheduled to announce on Friday.
Obama clearly takes center stage during convention week, but McCain's advisers hope to use even that to their advantage by painting Obama as an overexposed celebrity receiving fawning press coverage.
McCain strategist Sarah Simmons set the expectations: "Obama's stadium address on Thursday — the 45th anniversary of Rev. Martin Luther King Jr.'s 'I Have A Dream' speech — will result in effusive and overwhelming press coverage. ... This coverage will be impenetrable and will undoubtedly impact the polls." Another McCain adviser said the campaign plans to take pokes at the press coverage to rile up media-skeptical supporters.
The campaign recently renewed its celebrity theme with a Web video mocking the first-term Illinois senator as "The One." Rife with biblical references and sarcasm, the ad links Moses parting the Red Sea with Obama bodysurfing while on vacation in Hawaii.
"'The One' returns, this time to lead us to the road to Denver," the ad says, a not-so-veiled reference to the Road to Damascus. "In Denver, you will see the light."
The tongue-in-cheek ad is only appearing on the Internet and is meant to underscore what the McCain camp believes is pro-Obama coverage. With more than 15,000 reporters in Denver to cover the Democrats' convention, McCain advisers said they will use the coverage as yet another way to show McCain as the underdog.
Republican officials around the country took their cue and started repeating the complaint. In Ohio, where McCain has announced a 10,000-person rally for Friday, Republican Party executive director Jason Mauk dutifully repeated McCain's criticism of Obama.
"We will encourage voters to look beyond the glamour of Barack Obama's celebrity status to his inexperience and lack of accomplishment," said Mauk. "Even Democrats in Ohio are calling on Senator Obama to offer something more than a lofty speech. Ohioans are beginning to wonder if there's anything more to Barack Obama than his trusty TelePrompTer."