"We've closed in the last week," said McCain, who was campaigning later in Iowa. "We'll continue to be very competitive in many of the battleground states."
Recent polls have shown McCain trailing Obama both nationally and in some of the battleground states, including Iowa. A Newsweek poll released Saturday showed Obama with a 13-point lead over McCain nationally.
Questioned about his standing, McCain said the race is close and insisted he will emerge victorious on Nov. 4.
"This is going to be a very close race, and I believe I'm going to win it," he said. McCain said he's been heartened by the size of the crowds and the level of enthusiasm at his events.
He also rejected the notion that his running mate, Alaska Gov.
Sarah Palin, isn't qualified to be president and is hurting the campaign.
"I don't defend her. I praise her," McCain said. "She is exactly what Washington needs."