(Reuters) - The Los Angeles Dodgers had to work overtime to earn a sweep of the New York Mets on Sunday, exploding in emphatic style after a mammoth contest to outlast the Mets 8-3 in 12 innings.

The Dodgers unleashed a five-run 12th to break out of a 3-3 tie and completed their dominant three-game series with a victory that took nearly five hours to complete.

Juan Rivera homered in the fourth inning and visiting Los Angeles took a 3-1 lead in the sixth, but the Mets (47-48) battled back with a Daniel Murphy RBI in the seventh and a game-tying score in the ninth against reliever Javy Guerra.

Pinch-hitter Matt Treanor delivered the go-ahead two-run single in the 12th, where the Dodgers also got a two-run double by Adam Kennedy.

"I was just looking for something that I could drive up through the middle," Treanor said.

"I was just a little piece of this win. These guys came out and battled for four-plus hours."

Los Angeles starter Nate Eovaldi struck out seven batters but left in the fifth having allowed one run, and the bullpen took over from there.

Rookie Josh Wall pitched the 11th and got the win in his Major League debut as the streaking Dodgers (52-44) pulled to within 1 1/2 games of the first-place San Francisco Giants in the National League West.

"As long as I've envisioned (my debut) it was a situation like that with the game on the line," Wall said.

"I'm glad that I could get in there and do well. The only thing I was thinking about was 'get strike one over,' then I settled in and felt good."

Slumping New York has lost eight of their last nine games to slip below .500.

Starter Jonathon Niese allowed three runs in seven innings and Ramon Ramirez allowed the five runs in the 12th.

(Writing by Jahmal Corner in Los Angeles; Editing by John O'Brien)