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 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 had a sacrifice fly in the second, a two-run single in the fifth, a homer leading off the seventh and bases-loaded walk in the ninth.The home run in the seventh hit the basket and initially was ruled a triple. He was standing on third when the call got changed, and at that point, Tejada had two words for the umpire: “Thank you.” 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 and drove in three runs before leaving with a strained right quad before the top of the ninth. He’s day to day.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.The Cubs were leading 4-2 heading into the fifth when Angel Pagan led off 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.Luis Hernandez, Carlos Beltran and Davis followed with singles as the Mets 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 RBI base hit.

NOTES—-Mets ace Johan Santana was scratched from Tuesday’s start against Washington because of a strained left pectoral muscle. … 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.