Barack Obama raked $7.8 million Sunday at three separate fundraisers in San Francisco, telling a VIP dinner crowd -- many of whom paid $28,500 to attend -- that he would win the presidency in November but to expect a tough battle with Republicans in the meantime.

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"John McCain, all he wants to do is talk about me," Obama told supporters. "They know they can't win on the issues. So what they'll do is they'll try to scare people: 'He's risky. He's risky. We're not sure."'

Obama was introduced at the dinner by House Speaker Nancy Pelosi, who called him "a leader God has blessed us with at this time."

Obama has maintained a strong fundraising pace, bringing in $51 million in July to McCain's $27 million. But his campaign has also been spending at a rapid clip and the Illinois senator has turned down public funding for the general election campaign, requiring him to keep up a robust fundraising schedule for the fall.

It was the second full-throated attack Obama made on McCain after a Saturday forum at a California megachurch, where the two embraced briefly.

At a town hall meeting with several hundred union members, Obama said he had had a great conversation with McCain at the forum at Saddleback Church sponsored by the popular evangelical pastor Rick Warren. The two candidates shook hands, briefly hugged and stood onstage with Warren, the first time they appeared together in public since the end of the primary season.

But Sunday, after praising the Arizona senator as a "genuine American patriot," the Democratic presidential hopeful got back to business -- methodically tearing into McCain's health care, tax and energy policies and criticizing his advisers.

Obama called the U.S. economy a disaster thanks to "John McCain's president, George W. Bush," and chided his Republican rival's campaign team for trying to make him look unpatriotic and weak.

"McCain says, 'Here's my plan, I'm going to drill here, drill now,' which is something he only came up with two months ago when he started looking at polling," Obama said of McCain's energy policy.

The GOP hopeful has become a vocal proponent of offshore oil drilling as a way to ease U.S. dependence on foreign oil and has criticized Obama for failing to embrace it as a way to help bring down oil prices. Obama noted that McCain had long opposed lifting the moratorium on offshore drilling.

The Illinois senator also criticized McCain's advisers as "the same old folks that brought you George W. Bush. The same team." He noted many had been lobbyists in Washington before McCain asked them to sever all lobbying ties.

Obama added, "They say this other guy is unpatriotic, or this guy likes French people. That's what they said about Kerry," referring to the 2004 Democratic nominee who lost narrowly to Bush. "They try to make it out like Democrats aren't tough enough, aren't macho enough. It's the same strategy."

Earlier this summer, McCain handed day-to-day operation of his campaign to Steve Schmidt, a veteran GOP strategist who was a spokesman for Bush during the 2004 campaign. Most of his other top advisers are longtime loyalists who have worked for McCain for years.

Even so, Obama stepped to McCain's defense when a voter criticized his Vietnam era record. A Naval aviator, McCain spent 5 1/2 years as a prisoner of war there after being shot down and badly wounded.

"Respectfully I'm going to disagree with you on McCain and his service," Obama said. "I think his service was honorable. He deserves respect."