CHICAGO -- There was little doubt where Kris Bryant's long shot was headed in the first inning Monday.

The Chicago Cubs third baseman hit a blast that landed in back of the newly reopened left field bleachers, christening the new seats with his second home run of the season and the first of his career at Wrigley Field.

Bryant's homer off Mets starter Jacob deGrom opened a 2-0 lead, and the Cubs went on to beat New York 4-3 in the opener of a four-game series.

"It's really nice for him to get that monkey off his back here at Wrigley," Cubs first baseman Anthony Rizzo said.

Cubs manager Joe Maddon added, "(Bryant's) ball was properly struck."

Rizzo stepped up next and homered to right to open a 3-0 lead, and second baseman Addison Russell singled home what proved to be the decisive run in the fourth.

Left-hander Jon Lester (3-2) threw six innings of three-run ball for his third consecutive win, and closer Hector Rondon worked a scoreless ninth for his seventh save as the Cubs snapped a two-game losing streak.

"I thought (Lester) had a better cutter -- especially early in the game -- the curveball was a very pertinent pitch for him tonight," Maddon said.

The loss was just the second in six games for the Mets, who lead the National League East.

It was the first game this season with at least part of Wrigley Field's bleachers open. The right field bleachers remain under construction as part of a major renovation.

DeGrom (3-4) allowed four runs on five hits and four walks with five strikeouts in five innings.

"I had a hard time all night using every pitch. I really wasn't locating anything," deGrom said. "The first inning, I hit the leadoff guy and then make a mistake in the middle and give them back-to-back (homers). I think it was one of those days, and now I've got to turn the page."

Mets manager Terry Collins knew right away that deGrom's control was suspect.

"When he had to make a pitch, he didn't make it, he couldn't make it," Collins said. "It starts with that. You can talk secondary pitch all you want. You've got to locate your fastball, and that's what made him so good last year."

Lester gave up consecutive solo home runs to first baseman Lucas Duda and shortstop Wilmer Flores in the sixth inning but got out of the frame by striking out pinch hitter Ruben Tejada.

Lester allowed five hits, walked four and struck out six while throwing 110 pitches in his fourth straight quality start.

Bryant was 1-for-2 with two RBIs and two walks. Chicago left fielder Chris Coghlan went 2-for-4 with a run.

Duda finished 2-for-4 with an RBI and a run.

In the bottom of the first, Bryant sent a 2-1 deGrom offering to the rear of the left field bleachers to drive in leadoff batter Dexter Fowler.

Rizzo, batting third, took the first pitch from deGrom, then lifted a solo home run into 15 mph winds from the west to the still-under-construction right field bleachers for a 3-0 lead.

The Mets had runners at second and third with two out in the fourth when catcher Kevin Plawecki singled home left fielder Michael Cuddyer from third to break the shutout.

Russell got the run back when he looped a two-out single to right in the bottom of the inning, scoring Coghlan for a 4-1 lead.

NOTES: New York RHP Noah Syndergaard makes his major league debut Tuesday after starting the season 3-0 with a 1.82 ERA for Triple-A Las Vegas. Syndergaard will face Cubs RHP Jake Arrieta (3-3, 3.41 ERA). ... Cubs 2B Addison Russell had a 12-game hitting streak end Sunday, but he reached base safely in a 14th consecutive game Monday. ... Mets starter Jacob deGrom entered Monday with the fourth lowest ERA in the major leagues (2.25) dating back to June 21, 2014. ... Over the first 10 days of May, the Mets' 1.52 ERA was the major league's lowest.