Cubs top Mets, 5-2, to take first two games of the series
Feldman (6-5) struck out six and had a two-RBI single in the fourth off Jonathon Niese (3-6) to help himself on the way to his first win since May 29.
Kevin Gregg got the last three outs for his ninth straight save and Chicago beat the Mets for the second day in a row, after losing five of seven before getting to Queens.
Gregg allowed a leadoff single to Marlon Byrd and third baseman Cody Ransom mishandled Justin Turner's hard smash with one out, but John Buck and Juan Lagares flied out.
The Mets got a run back in the bottom of the eighth on Jordany Valdespin's single off Carlos Villanueva, but David Wright struck out with runners on second and third and fans streamed for the exits.
The Cubs stranded 10 runners in the first seven innings before breaking it open in the eighth. Scott Rice allowed a hit and a walk around a sacrifice, then Brandon Lyon came on and gave up a single to load the bases before walking Cody Ransom to force in a run. Castro then had his hit.
Before his double bounced over the wall, Castro had stranded five runners and struck out three times, including with the bases loaded to end the fourth.
In the fourth inning, Wright followed Daniel Murphy's leadoff double with a double of his own to cut the lead to 2-1, but he was stranded at second.
Niese left with two outs in the fifth inning and a man on second. He finished having allowed two runs, six hits and four walks with five strikeouts. He is 0-2 in his past four starts.
NOTES: Mets GM Sandy Alderson told season ticket holders Saturday morning that ''over the next six months or so, we will be in a position make some significant acquisitions, whether it's through free agency or a trade. ... Wright tied his career best by reaching in nine straight plate appearances, but his deep drive to left in the sixth inning was caught at the wall. ... In the third inning, a fan hustled to get a foul ball that had gone uncaught and was rolling around on the concourse. He stood up and handed the ball to a child seated just above where it had fallen, and got a polite hand from the crowd and a shake from a security guard. ... 2B Valdespin let Ransom move up a base in the first when he misfired while attempting to return the ball to Niese after Ransom's single. He was charged with an error. ... Ransom had two singles, two walks and reached on an error. ... TheCubs were 3 for 18 with runners in scoring position.