George Foster hit a grand slam and John Christensen followed with another home run in the third inning as the Mets defeated Chicago, 5-3, yesterday, completing a four-game sweep in New York and giving the Cubs their ninth straight loss.

The losing streak is the Cubs' longest since they lost 13 in a row in June 1982.

"With the way we were, this is probably the biggest series we'll have all year," Mets Manager Dave Johnson said. "The sweep is great after what the Cubs did to us last year (winning 12 of 18). This takes away the psychological edge they had."

Sid Fernandez (2-4) gave up two runs on five hits over six innings, striking out 10 as he ended his four-game losing streak. Roger McDowell, in his first appearance since suffering an ankle injury June 7, finished for his fourth save.

After Ray Fontenot (1-3) retired the first two batters in the third, Kelvin Chapman singled and Ray Knight hit a grounder that shortstop Chris Speier bobbled for an error.

Gary Carter walked on four pitches, loading the bases, and Foster hit his ninth homer of the season and 12th career grand slam. Christensen hit his third home run.

A crowd of 37,203 enabled the Mets to set a four-game club attendance record of 172,292 and pushed season attendance to 1,035,729, the earliest the team has gone over 1 million.