New York ? For more than a decade, Tom Glavine helped put the Atlanta Braves on top.

Now, he’ll try to topple them.

Glavine, the most sought-after pitcher on the free-agent market, reached agreement with the New York Mets on a three-year contract, his agent said Thursday night.

Glavine, 36, had spent his whole career with the Braves, winning two Cy Young Awards and posting five 20-win seasons.

But their NL East rivals, the Mets and Phillies, showed much more interest in the left-hander than his old team and it came down to a choice between New York and Philadelphia.

“It was one of the toughest decisions he’s ever had to make,” said his agent, Gregg Clifton. “There wasn’t really one thing that decided it. He just made a decision.”

Glavine was believed to have gotten a $35 million contract with a vesting option that could make the deal worth $42.5 million.

“We have reached an understanding with Tom Glavine on the structure of a multiyear contract,” Mets spokesman Jay Horwitz said. “The completion of an agreement is subject to Tom passing a physical examination on Monday, Dec. 9.”

Braves president Stan Kasten, who was attending an Atlanta Hawks game at Philips Arena, declined comment. He said the team probably would hold a news conference Friday.

Glavine did not return a telephone message left at his home.

“Although we were disappointed to hear that he has opted to sign with the Mets, we appreciate the opportunity we had to try to sign him,” Phillies general manager Ed Wade said in a statement.

“Tom was as professional and poised in our contract discussions as he is on the mound, and we wish him well … against all our division opponents.”

Fellow Cy Young winners Roger Clemens and Greg Maddux also are free agents, but have hardly generated interest so far in the offseason.

With Glavine in their rotation, the Braves won 11 straight division titles ” and became the Mets’ biggest nemesis.

When Atlanta won its only World Series championship in 1995, Glavine pitched the clinching game. He gave up only one hit over eight innings and beat Cleveland 1-0 in Game 6 for the title.