CHICAGO -- The Mets' rookie brigade was on full display Sunday, and the newbies helped New York avoid a Wrigley Field sweep.

Rookie shortstop Ruben Tejada, hyped for his slick glovework at shortstop, drove in five runs and hit his first big league homer, while fellow first-year player Jon Niese bounced back from a couple of rough outings, while helping himself with a pair of RBI singles. The Mets beat the Cubs, 18-5, before 40,788 in the series finale at Wrigley Field.

Five rookies were in the starting lineup for the second straight day, and they drove in 12 of the runs. Tejada led the way with by far his biggest day as a big leaguer.

"He's a good player," said Mets manager Jerry Manuel. "He's a nice, complementary piece when all the other players are playing their roles."

Cubs starter Ryan Dempster was erratic from the start, perhaps best evidenced when he allowed Niese's RBI single in the second. Niese was batting .133 with one RBI entering the game. His hit put New York up, 2-1, and capped a two-run rally in the inning. Rookie Lucas Duda got things started with a leadoff walk. Duda has looked like a player who isn't going to put the ball into play too often, as he's walked or struck out in 10 of his first 20 big league plate appearances, and is 1-for-17 overall. He scored on a double to right by rookie catcher Josh Thole, who just missed an extra-base hit earlier in his at-bat when he sliced a drive that fell just left of the foul line in the left-field corner.

Niese got off to a slow start, allowing three hits on hard-hit balls in the first, but was propped up by a pair of early around-the-horn double plays. He got Chicago's Xavier Nady to bounce into an inning-ending twin killing with two on in the first. He also induced Starlin Castro to hit into a 5-4-3 double play in the third, and later got Castro on a double play in the fifth.

Niese's luck ran out when hot-hitting Aramis Ramirez launched a 1-2 changeup into the left-center-field bleachers in the third. Ramirez fouled off seven pitches in the at-bat. The homer came one batter after Niese issued a two-out walk to Byrd and put the Cubs up, 3-2.

"He was fouling a lot of good pitches off," said Niese. "I was throwing up and in on him, I was throwing cutters on him, curveballs down and in, and he kept fouling balls away. I threw a changeup away and I thought I threw a good changeup, but he put a good swing on it."

In the fourth, Niese slipped on the mound while delivering an 0-1 pitch to Chicago's Tyler Colvin and uncorked his offering well wide of Thole's mitt. Niese's front knee appeared to actually be on the ground as he threw the pitch. The Mets' training staff trotted onto the field to check on the lefty, who threw a couple of warmup pitches and remained in the game. However, his next pitch was lined by Colvin off the ivy in left-center for a triple. Colvin scored on Geovany Soto's sacrifice fly to center, putting the Cubs ahead, 4-2.

"It was just one of those things," said Niese. "My cleat never caught the dirt, my leg went out from under me, and I just fell."

From that point on, Niese was mostly effective, allowing five runs and eight hits in six-plus innings. He departed after allowing a homer to Soto leading off the seventh. Niese had allowed 15 runs (10 earned) in his previous two starts.

"I thought he threw the ball well," said Manuel. "He got some timely double plays. I thought Ramirez had a good at-bat against him. Soto put a good swing on him the last time, I was trying to push him, but it didn't work out.

"I was happy with the way he threw. It looked like he had a quick arm."

The Mets' offensive explosion gave Niese a nice cushion as he works to regain his form from earlier this season.

"I felt good," said Niese. "Obviously it doesn't really look good on paper, but I'm thankful our offense did great job today.

"I felt [like] my curve was good. My curveball needs a lot of work. I need to get it back to where it used to be."

The Mets caught a break in the fifth. Angel Pagan led off with a fly ball to the warning track in right, which Colvin, playing right field, appeared to track down. Colvin dropped the ball after taking a stride or two, and the umpires ruled that he didn't hold it long enough. Pagan, who had started to curl back to the dugout after reaching first base, recovered and scampered into the second, setting up New York's key inning in the contest. The play was scored a two-base error on Colvin.

"He did a great job getting to it and was concerned about the wall and arriving on the track and everything," said Cubs manager Mike Quade. "He didn't have a reason to make a transfer because he had no throw, but was anxious to get the ball out of his glove because he caught it. Instead of trying to settle it ... he was anxious to say, 'I got it' and it didn't work out too well. It's just an awkward play."

Pagan went to third on Luis Hernandez's single to right, and scored on Carlos Beltran's bouncing single up the middle, cutting the Chicago advantage to 4-3. One batter later, the Mets had the merry-go-round going. Rookie first baseman Ike Davis grounded a single to right. The hard-charging Colvin gunned a throw at Soto, but Hernandez slid around the tag for the game-tying single. The Mets' third straight hit left runners on first and second, nobody out, for Mike Hessman, who walked, loading the bases for Duda and nobody out.

Dempster recovered to strike out Duda and Thole, then got Tejada down 1-2 in the count. However, Tejada looped a single to shallow center, scoring Beltran and Davis.

"The hit [Tejada] got with the bases loaded against Dempster was the biggest hit of the day for us, because we had been horrible with the bases loaded," said Manuel. "We had two [straight] punchouts at that time and he had two strikes on him, and he got the base hit, and we eventually put up a five-spot.

"I've always thought that he has a good swing. I still feel that. He lacks a little strength and speed, but he has the fundamentals and the foundation for a good swing. He's the type of guy that's always in the middle of things."

Niese followed with another RBI single, thus tripling his total for the season during the course of the game, capping a five-run rally and putting the Mets up, 7-4, and chasing Dempster. All told, the Mets sent 10 to the plate in the fifth.

In the seventh, Tejada tacked on New York's eighth run with a homer into the basket just left of the batter's eye in center. At first, the ball appeared to stay in play and Tejada raced around the bases and slid into third with an apparent triple before being waved in by the umpires.

"I hit the ball good, but I can't see the ball out there, so I kept running and slid into third," Tejada said. "The umpire said, 'Keep going,' and I said, 'OK, thank you.'"

Davis added a two-run homer in the Mets' five-run eighth. Davis had four hits and drove in three runs, homering for the second straight day after going six weeks without a dinger. Among the veterans, Beltran reached base five times, with two hits and three walks.

The Mets' breakout day with the bats marked a couple of high-water marks, as both the 18 runs and 21 hits were season highs. They scored five runs in an inning three times, marking the first time in franchise history that has happened. The 18 runs were New York's most since Aug. 24, 2005, and the hit total was the team's highest since April 29, 2000.

Not bad for a bunch of freshmen.