Too often this season, Mets manager Terry Collins has been justified in believing he can only count on his fingers. His bullpen fails when his hitters don't; his regulars keep playing their way into platoon roles (or demotions to Triple-A); some fielders can't dance and some sluggers can't rock and roll.

Yet his delicate balance between an evolving chemistry and witches' brew, between staying the course with so many young wannabes and cracking down on the team's laggards, continues to hold together his fragile team.

Collins' decision Thursday night to rethink rookie Eric Campbell's role as a backup first baseman and pinch hitter paid off handsomely in a 5-3 win that prevented a three-game sweep by the Dodgers.

"Happens all the time," Collins said. "You put a guy in for offense and his defense saves the game. I call it a sign that we were supposed to win that."

The urge to keep Campbell's smoking bat in the lineup brought the Mets their first run, via a second-inning sacrifice fly. More importantly, Collins' concern that Campbell might be "uncomfortable defensively" in leftfield was thoroughly erased in the eighth inning.

The Mets had just taken a 4-3 lead. Yasiel Puig -- whose sprawling, backhanded catch of Wilmer Flores' second-inning fly was ever more spectacular -- was aboard after a monster double off the centerfield fence. Then Campbell executed a full-out, belly-flop, diving stab of Hanley Ramirez's line drive and doubled Puig off second base.

"Off the bat I thought it was going to be a one-hopper," Campbell said, "so I was charging hard to try to make a play at the plate, because that's the tying run. I guess he hit it too well. It stayed up a little bit longer and I was able to get my glove under it."

Not 24 hours earlier, Collins had voiced a reluctance to change Campbell's defensive assignment. But he had telephoned Campbell's Las Vegas manager, Wally Backman, early Thursday to ask if he was taking a chance with Campbell in left. "Absolutely not," Backman said.

Of course, the victory was not easy. Or neat.

Winner Jonathon Niese (3-3, 2.70), after cruising from the third through the sixth without allowing a hit as the Mets pulled ahead 3-1, was victimized by former Met Justin Turner's two-run homer in the seventh.

"I wouldn't say I lost focus," Niese said. "I lost my aggression and got complacent out there a little bit. Just aiming the ball. You make a mistake and [Turner] will punish you."

That was after back-to-back doubles by Anthony Recker and Niese himself -- no typo there; a Mets pitcher got a hit -- and Turner's two-out error produced two runs in the fifth.

Juan Lagares' two-out single in the bottom of the seventh took back the lead for the Mets, who added an insurance run in the eighth when David Wright singled and scored on Curtis Granderson's triple.

Then former starter Jenrry Mejia threw a perfect ninth inning for a second consecutive night. "I enjoy my role," Mejia said. "I enjoy my bullpen; it's my new house over there."

There remain challenges aplenty. But Collins was mulling the possibility of Campbell at middle infield positions to keep him in the lineup. Even emergency catcher.

Said Collins, "Why not?"