Tom Seaver pitched a three-hitter and tripled home a run in New York's three-run second inning as the Mets defeated the Pittsburgh Pirates, 6-0, in the first game of a doubleheader last night in Shea Stadium.

Mookie Wilson's eighth-inning bloop single won the second game for the Mets, 7-5.

Pirates reliever Kent Tekulve (0-1) had two outs in the eighth inning of the second game, which was tied at 5. But he walked Brian Giles and pinch hitter George Foster, then Wilson singled. Giles scored and, when catcher Steve Nicosia mishandled left fielder Brian Harper's throw home, Foster scored, too.

Reliever Carlos Diaz (1-0) got the victory and Neil Allen pitched the ninth for his second save.

In the first game, Dave Kingman had a two-run homer, his second, in the seventh inning to help the Mets end a six-game losing streak.

The victory was Seaver's first this year, although he pitched well in two previous starts. Seaver has pitched 22 innings this season and given up only two runs on 11 hits. Against the Pirates, he struck out nine and walked three.

The shutout was his 55th in the majors, tops among active pitchers in the league.