The New York Mets knotted the World Series against the A's in Oakland yesterday on three unearned runs in the 12th inning to win the second game, 10-7, and to cap a marathon contest fraught with errors and marked by one significant close call.

The series, tied at a game each, now goes to New York for a Tuesday game.

Willie Mays keyed the 12th inning rally with a run-scoring single to put the Mets ahead, 7-6. Earlier, in the ninth frame, Mays's failure to track what turned into Deron Johnson's double allowed the A's to tie the game and send it into extra innings.

The A's chased Mets starter Jerry Koosman in the third inning while building up a 3-1 lead. The A's got two in the first on a double by Joe Rudi, a triple from Sal Bando, and a double to Jesus Alou. Oakland got its third run in the second on a triple by Bert Campaneris and a single from Rudi.

However, the scrappy Mets topped balls all around the infield in the sixth inning to grab four runs and the lead, 6-3. The New Yorkers kept the bases jammed and Oakland reliever Darold Knowles made a two-run throwing error.

Mets' Reliever Tug McGraw, who went on to win the game, took the hill in the sixth frame but yielded a run in the seventh on a hit-batsmen, a walk, and a double to Reggie Jackson.

The Mets carried that 6-4 bulge into the bottom of the ninth. But Johnson reached second when Mays fell down trying to glove his fly ball and after McGraw retired the next two, Bando walked. Jackson and Gene Tenace delivered with singles to tie the game.

In the tenth inning, the Mets' Bud Harrelson was thrown out in a close play at the plate while trying to score on a fly ball, and an apparent New York triumph dissolved with the jerk of umpire Augie Donatelli's thumb.

But Harrelson doubled to open the Mets' 12th and went to third on McGraw's scratch single. After loser and reliever Rollie Fingers got the next two batters, Willie Mays stepped into the box.

Mays, in his last season as a player, lashed a single to center to put the Mets ahead, 7-6. Two consecutive errors by second baseman Mike Andrews opened the way for three more runs and a Mets lead of 10-6.

George Stone relieved McGraw in the 12th as Reggie Jackson tripled to lead off and later scored. Stone held on as the Mets won.

In the 4-hour, 13-minute tilt, a porous Oakland defense committed five errors, as 49,151 looked on in Alameda Country Coliseum.