WASHINGTON -AP- T.J. Rivera will not forget his first major league home run anytime soon.The rookie second baseman belted an 0-2 pitch off Mark Melancon into the left-field seats with one out in the 10th inning to lift the New York Mets to a 4-3 victory over the Washington Nationals on Tuesday night."All I could do was go up there and try to have a good at-bat," Rivera said. "He left something up and luckily I was able to put the barrel on it. That was pretty much my whole concept, my whole idea for that at-bat was really just compete because I'd never faced him before." The Mets pulled within nine games of Washington in the NL East and remained a half-game ahead of St. Louis in the NL wild-card race. New York has won eight of its last 10 and is 17-6 since Aug. 20, gaining 3 1/2 games on Washington in that stretch.Jeurys Familia (3-3) earned the victory despite surrendering two runs in the ninth to blow his fourth save of the season. Left-hander Jerry Blevinsstruck out Daniel Murphy for the final out to earn his first save since 2012."I was trying to put it into play," said Murphy, who earlier had two hits and has hit safely against the Mets in 18 consecutive games this season. "I was unsuccessful."Rivera, who won the Pacific Coast League batting title this season and entered the night with 41 career at-bats in the majors, probably would not have played if Wilmer Flores wasn't dealing with a stiff neck. Manager Terry Collins gave Rivera the start, and the move paid off even before the home run.Rivera had an RBI single in the third and a sacrifice fly in the fifth, then took Melancon (2-2) deep after the Nationals rallied to force extra innings."Somebody has to surprise you," Collins said. "Somebody you don't expect has to come through, and tonight it was T.J."Washington mustered only four hits in the first eight innings, but quickly got to Familia in the ninth. Murphy led off with an infield single, and third baseman Jose Reyes threw Bryce Harper's grounder into the seats.Anthony Rendon and Wilson Ramos then delivered consecutive singles to tie it.Familia then got Ryan Zimmerman to line out and pinch-hitter Clint Robinson to hit a soft liner to second that fooled pinch-runner Wilmer Difo, who was doubled off first."We have arguably the best closer in the game and they hit four groundballs and three of them didn't get out of the infield and the game's tied," Collins said. "He was frustrated by it and we certainly understand it, but we wouldn't be sitting where we are without him."After Jayson Werth's two-out single off Fernando Salas in the 10th brought the winning run to the plate, Collins called on Blevins. He got two strikes on Murphy, who then worked a full count before missing a curveball to end it."He's so good and an MVP candidate for a reason," Blevins said. "You try to take advantage of some aggressiveness and get him to swing at your pitch."Noah Syndergaard struck out 10 over seven innings for the Mets, yielding just one run and four hits."When you run probably your best pitcher out, you have to win that game," Collins said. "You have to win this game tonight with Noah on the mound. He pitched great."Nationals starter A.J. Cole allowed three runs and nine hits in five innings.SYNDERGAARD'S MILESTONESyndergaard's 10-strikeout outing of the season gave him 205 for the season. The 24-year-old is the fifth Met to record 200 strikeouts at that age or younger, joining Tom Seaver (1968 and 1969), Jon Matlack (1973), Dwight Gooden (1984-86) and Sid Fernandez (1986).ZEROES FOR RZEPCZYNSKIWashington reliever Marc Rzepczynski retired the lone Met he faced and has not allowed an earned run in nine appearances since being acquired from Oakland on Aug. 25. Rzepczynski has yielded four hits and three walks in 8 1/3 innings since joining the Nationals.