"Basically, we're ... ," Mattingly said. "We're just not that good."
The Dodgers have lost six of their last eight games. They are only one game over .500 and trail the San Francisco Giants by a season-high eight games in the National League West.
"Home, away, whatever," Mattingly said. "I don't know what that has to do with it."
The Dodgers looked particularly helpless on this night, as they were limited to a hit over the first seven innings, a bunt single by Dee Gordon to lead off the bottom of the first inning.
Mattingly had little to say about the loss and called on his players to be accountable.
"I really think you should talk to them," he said. "I'm tired of answering the questions, honestly."
Before the game, Mattingly implied some of his players were more concerned about themselves than they were about the team.
Asked about how Carl Crawford's anticipated return from the disabled list could affect Matt Kemp's playing time, Mattingly replied, "I'm not thinking about any of that right now. Honestly, so tired of talking about individual guys instead of talking about us as a club and how we are going to win games. There's so much focus on individual guys that we've gotten away from, 'What's the team doing? How are we going to win games?' "
Mattingly said he wasn't blaming the situation in the outfield, where Kemp, Crawford and Andre Ethier have shared time in the two positions not occupied by Yasiel Puig. The three former All-Stars have been less than pleased with the situation, particularly Kemp, who was moved from center field to left.
Hanley Ramirez is in the final year of his contract and continues to wait for an extension. He is batting .253 and ranks among the worst defensive shortstops in the majors. For his part, Ramirez has said his uncertain future hasn't affected his play.
Furthermore, the bullpen has lacked consistency.
Mattingly is looking for the Dodgers to recapture the feeling that helped them turn around their season last year.
"I think when we were starting to put things together last year, you felt a real, true team focus, just a collective group," Mattingly said.
Mattingly recalled a favorite saying of former manager Tom Lasorda.
"Tommy says it all the time, and it seems corny at times, but he says, 'We all have to get on one end of the rope,' " Mattingly said. "But as many times as you've heard Tommy say it, it's absolutely true. When that group gets going in one direction and that focus is purely to win a game no matter who gets the attention or who gets this or who gets that, I think it's always better.
"That's the one thing you don't measure with numbers and that's the power you talk about with a group. We haven't felt that as a team, and I think it's the one area that we're missing. To be absolutely honest with you, I think that's the one thing we're missing at this point, a collective group fighting and pulling in one direction trying to win a game, without any concept of this guy or that guy or this guy."