NEW YORK – Once Grady Sizemore hit a leadoff home run, the Cleveland Indians were headed to the AL championship series while the New York Yankees were braced for a showdown with their boss.

Paul Byrd and the Indians bullpen closed out New York 6-4 in Game 4 last night, completing another first-round debacle for the Yankees that might cost manager Joe Torre his job.

The Yankees came in streaking, overcoming a 21-29 start to win the AL wild card. But they were done in by poor pitching, an insect invasion and the latest October vanishing act by Alex Rodriguez, whose bat was quiet until a solo home run in the seventh inning.

The pesky Indians, who wasted a three-run lead in Game 3, chased Chien-Ming Wang in the second and burst ahead 4-0. Byrd kept wiggling out of trouble, and Victor Martinez’s two-run single made it 6-1 in the fourth against reliever Mike Mussina.

A day after averting a sweep, New York put runners on in each of the first seven innings. But when it counted, its high-octane offense fell flat once again, with late homers by Rodriguez and Bobby Abreu not enough.

Cleveland moves on to its first ALCS since 1998, opening Friday night at Boston. The Indians were only 2-5 against the Red Sox this season, but will have aces C.C. Sabathia and Fausto Carmona rested for Fenway Park.

The Indians are seeking their first World Series title since 1948.

Bewildered New York opens yet another offseason of turmoil, another October over nearly as soon as it began. All eyes will be on owner George Steinbrenner, who said over the weekend that he didn’t think he’d keep Torre as manager if New York bowed with another early exit.

Torre managed the Yankees to four World Series titles in his first five years and reached the playoffs in all 12 of his seasons. Yet, that might not be enough for Steinbrenner, impatient his team of multimillionaires has gone seven years in a row with no title and hasn’t even gotten past the first round since 2004.