NEW YORK — Last night the Red Sox began their final series in an historic soon-to-close New York ballpark. Next spring, they’ll help open a new New York ballpark one borough over.

On the final weekend of exhibition play, the Red Sox will play a two-game series at Citi Field, the new home of the New York Mets.

Citi Field is being constructed across the parking lot from Shea Stadium, which like Yankee Stadium is closing at the end of this season. Citi Field, an $850-million project, will seat 45,000 fans.

The exhibition games — which will probably take place April 3-4 — will be the first at the new ballpark. The N.L. schedule calls for the Mets to open the 2009 season on the road before hosting the San Diego Padres in the first regular-season game at Citi Field on April 14.

Tentative plans call for the Sox to open the regular season days later at Fenway, playing host to the Tampa Bay Rays. Opening the season at home is something of a rarity for the Sox, who have begun the season at Fenway just once (2005) in the last 12 seasons. Generally, Major League Baseball and the Sox prefer to have the club open on the road because of the uncertainty of New England weather in the first week of April.

The Red Sox are in demand as an exhibition opponent because they are one of best road attractions in the game. At the same time, such contests are lucrative for the Sox, earning guarantees of $500,000 or more for two games. Such guarantees help defray the cost of spring training.

smcadam@projo.com