NEW YORK — With Democrat Barack Obama on the other side of the planet, Republican presidential candidate John McCain stayed closer to home yesterday, visiting Yankee Stadium with former Mayor Rudy Giuliani.

The two high-profile Republicans are longtime friends, despite having campaigned against each other in the GOP primaries in which McCain ultimately prevailed. When Giuliani bowed out of the race, he immediately endorsed McCain.

Could Giuliani, who moonlights as the No. 1 Yankee fan, become the No. 2 on the Republican ticket?

"You hear all kinds of stuff, but I'm not thinking about anything but helping to get him elected," Giuliani said. "Beyond the fact that he's the candidate of my party, he's a very good friend."

The ex-mayor, whose name is also bandied about as a possible candidate for New York governor, said Obama's trip abroad highlights the gap in experience between the two candidates. Obama is traveling to Afghanistan, the Middle East and Europe.

"I think the fact that Barack Obama is kind of making his first tour, in essence, of the world, gives you an indication that John McCain is the man with the experience. John doesn't have to go for the first or second time to these places. He's been going for 20, 30 years. He knows the world," Giuliani said.

While Obama is overseas, McCain spent a low-key weekend in the Big Apple. On Friday night he appeared on "Late Night with Conan O'Brien," then spent Saturday in the Hamptons raising campaign money, including at the home of Ron Perelman, a billionaire whose controls Revlon Inc.

Yesterday morning he had a private meeting with New York City Schools Chancellor Joel Klein, whom McCain has publicly praised for his education reforms. Klein declined to comment as he entered McCain's hotel for the meeting.