Long man Kevin Correia was saddled with a second loss in relief, a throwing error by Justin Turner extending the 14th inning so Asdrubal Cabrera could blast a two-run homer that left the Dodgers 5-11 in extra innings. Turner was the third shortstop used, playing because recent callup Erisbel Arruebarrena can't hit or throw because of a sore shoulder.
Mattingly's offense stranded the bases loaded in the 10th and 11th innings, he lost Scott Van Slyke in the fifth inning when the outfielder's wife went into labor and the manager was second-guessed for a pair of late decisions. The Dodgers are hitting .170 this season with the bases loaded.
Despite all that, Mattingly was determined to accentuate the positive, which included Turner's two-run homer, comebacks to tie in the ninth (former Dodger Jayson Werth dropped Turner's sun-fly for an error) and 12th inning (on Carl Crawford's two-run homer), six scoreless innings from rookie Carlos Frias making his first Major League start and four quick outs from fellow rookie Pedro Baez.
"This is a good game for us," Mattingly said after ticking off each highlight, including good at-bats by Yasiel Puig and Andre Ethier. "The positives are our effort, determination and perseverance. That's what will get us where we want to go.
"We've been a club all year that has not seemed to come from behind, but the last couple times we've put the game right on the line. I'm really happy about a lot of stuff. Obviously, we had a few chances to win the game that didn't work out. But overall, a lot of good things."
The loss meant the Nationals took a series at Dodger Stadium for the first time since 2005, but the Dodgers' lead remained two games over the Giants, who also lost.
It was the club's longest game of the year in innings as well as time, five hours and 34 minutes, the eighth longest in club history. There were 51 players used, 18 of them pitchers that made 467 pitches.
One decision that Mattingly addressed came in the 10th inning. Catcher A.J. Ellis was walked with one out by Nationals reliever Craig Stammen. Dee Gordon singled Ellis to second. While every starting pitcher lobbied in the dugout to pinch-run for Ellis, Puig singled and Werth bobbled the ball in right, but Ellis was stopped at third by coach Lorenzo Bundy.
At that point, Mattingly pinch-ran for Ellis with infielder Arruebarrena. Mattingly said, in his opinion, Arruebarrena wouldn't have scored from second if he had been subbed for Ellis before Puig's hit.
"It didn't change anything," he said. "He is not scoring from there."
Mattingly explained that, without Van Slyke, he didn't feel he could afford to spend two players (a pinch-runner and replacement catcher) until Ellis reached third, where a faster runner would have a better chance to score on a sacrifice fly.
"OK, obviously then I had to," he said.
But Xavier Cedeno came on to strike out Adrian Gonzalez, then Aaron Barrett came on to fan Juan Uribe.
Mattingly also was asked about bunting with 30/30 prospect Joc Pederson in the 11th inning after no-out singles by Crawford and Turner. Mattingly praised Pederson for bunting the runners over, but he then sent up Matt Kemp, who was walked intentionally. Drew Butera popped out and Gordon struck out. He said letting Pederson swing was a consideration, but getting the winning runner to third base was a higher priority.
"We're out of players at that point and trying to win a game right there, but it was a consideration," he said, adding that Butera worked the count full before popping out.
Frias started to give the rotation an extra day of rest and line up the big three of Clayton Kershaw, Zack Greinke and Hyun-Jin Ryu for next weekend's Giants series.
He allowed three hits, none after the third inning, retiring the last 10 batters he faced. He struck out four and walked one in 77 pitches. The last Dodger to throw six scoreless innings in his first MLB start was Hong-Chih Kuo in 2006.