The Mets loaded the bases with two outs against Ryan Webb (4-3) and Tejada responded with a hit as New York finished off its first sweep at Citi Field since a June interleague series against Baltimore.
David Wright gave the Mets an early lead with a two-run homer in the first.
Bobby Parnell (5-4) was credited with the victory after hurling a scoreless top of the ninth.
Bryan Peterson had the only RBI for the Marlins.
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