"I don't know what it is," Collins said. "We didn't run the bases, we didn't play good defense, we didn't drive the runs in we needed to drive in. It was a combination of a lot of things. We didn't pitch very good."
The game started promisingly for the Mets, who hit four consecutive singles to spring to a 2-0 lead in the second inning.
Lucas Duda reached base with a two-out walk in the third inning before the first mistake of the night. Ike Davis ripped a double to right field and Duda was waved home by third-base coach Tim Teufel, but Duda stayed at third.
After a walk to Scott Hairston, the Mets left the bases loaded on a groundout by Daniel Murphy. Duda said he thought the ball was hit hard enough that it would bounce off the wall, and he didn't think he'd be able to score off the bat.
"That was my fault," Duda said. "I found Tim late. That was tough."
Then came the rare pitching woes for Gee, who had thrown at least 5 1/3 innings in all of his previous 14 starts. Gee allowed three runs in the bottom of the third inning on an RBI groundout, an RBI double and an RBI single. Gee also walked Starlin Castro and Bryan LaHair, who both scored.
Gee suffered his first career loss against the Cubs, allowing nine hits and four runs in five innings.
"That was the worst Dillon's pitched in a while," Collins said. "Nothing was going. Nothing was working. He battled through it and got us five innings. I was happy with that."
The final run charged to Gee came on a RBI double by Cubs first baseman Anthony Rizzo in the fourth inning. Rizzo finished 2-for-4 in his debut for the Cubs.
"He didn't act like much of a kid tonight," said manager Dale Sveum. "That was pretty impressive. You can't teach the way he is at first base, the mannerisms he has and all that."
Gee struck out LaHair with the bases loaded later in the fourth to keep the Mets within a run.
"I was pitching out of the stretch the entire game," Gee said. "I was out there trying to battle and make pitches. I left a couple up there that really cost me."
Cubs starter Randy Wells left after three plus innings with 79 pitches, but only three of the 10 combined Mets baserunners in the second, third and fourth innings scored.
The Mets drew five walks in the first four innings, but couldn't score any of those runners. They left at least one runner in scoring position in six of the first eight innings.
Pinch-runner Andres Torres was stranded at third base in the eighth inning. The Mets entered the game hitting .277 with runners in scoring position and two outs, the second-highest mark in the Major Leagues.
"We've played two bad baseball games here," Collins said. "We're a better team than what we've played."
Frustrations reached their peak in the bottom of the eighth, when Davis was ejected by first-base umpire Manny Gonzalez after arguing a tag he made on Cubs catcher Steve Clevenger.
"I think he said my glove touched him," Davis said. "That's probably why he wrung me. I didn't say anything too revolting. I didn't mean to touch him. I was just using my hand as a gesture."
Darwin Barney was at second base during the ejection and scored later in the inning after a throwing error by shortstop Ruben Tejada.
Davis and Gee both said regardless of the Cubs' recent struggles, no team can be taken for granted.
"They've pitched well, played good defense -- better defense than we've played," Davis said. "When you don't play good defense, you lose games.
"We need to clean it up. We're making a lot of errors and not taking advantage of opportunities to make outs."
Despite their recent mistakes, Duda said it's not time to get into a frenzy.
"We're all right," Duda said. "We don't need to panic. We hit some balls hard. We're making a few errors. We need to minimize that and keep doing what we're doing and we'll be all right."