Ruben Tejada hit his first major league homer and drove in five runs, Ike Davis also connected and the New York Mets erupted for 21 hits and pounded the Chicago Cubs 18-5 Sunday to avoid a weekend sweep.

The Mets' bats perked up for season highs in runs and hits even though David Wright got a day off and Jose Reyes was still nursing a strained right oblique. They scored five runs in the fifth, eighth and ninth innings while winning for just the second time in seven games.

Tejada, who had never knocked in more than a run, had a two-run single in the fifth and homered leading off the seventh.

Davis had four hits and drove in three runs while scoring three. He drove a two-run shot in the eighth for his 17th homer and second in as many games.

Jonathon Niese (9-7) delivered a pair of RBI singles and more than made up for his struggles on the mound. He went six-plus innings, giving up five runs after allowing a combined 15 in his previous two starts, but helped himself with a big day at the plate.

A .133 hitter entering the game, he chased Ryan Dempster (12-10) with an RBI single that capped a five-run fifth and turned a 4-2 deficit into a 7-4 lead.

Aramis Ramirez hit a two-run homer for Chicago and drove in three runs. Geovany Soto homered, but the Cubs lost for the fourth time in 12 games under interim manager Mike Quade.

Touched for seven runs in a season-low three innings against Pittsburgh last week, Dempster was no better this time. He lasted just 4 2-3 innings and allowed nine hits and seven runs, three of them earned.

He couldn't protect a 4-2 lead.

Angel Pagan led off the Mets fifth by reaching on a two-base error, when Tyler Colvin dropped his liner to deep right after a long run, and the Mets wound up sending up 10 batters.

Carlos Beltran and Davis followed with RBI singles that tied it at 4. After Mike Hessman walked to load the bases, Dempster struck out Lucas Duda and Josh Thole, but the Mets weren't finished.

Tejada hit a two-run single and Niese, who had singled in a run in the second, chased Dempster with another one.

While Dempster struggled, it was also a rough afternoon for Starlin Castro.

He went 0 for 4 after becoming the first Cubs rookie in 66 years with six straight multihit games with two double plays and what amounted to a third in the eighth.

Castro started trotting off the field, apparently thinking the inning was over, when Davis fielded his grounder to first and threw to second. Problem was, that was only the second out and Tejada, the shortstop, threw back to Davis to end the inning on a sequence that was officially scored a fielder's choice and a pickoff.

Notes: Mets ace Johan Santana's status for his next start remained in question after a bullpen session Sunday. Santana's scheduled start Tuesday at Washington has been up in the air since he left Thursday's win over Atlanta with a strained left pectoral muscle. ... The Cubs' Carlos Silva said doctors told him he should "feel like a new guy" when he starts Tuesday against Houston. Silva, 10-5 with a 3.92 ERA, has not pitched since Aug. 1 because of a heart problem.