"It's a tough pill to swallow," Reds manager Dusty Baker said. "You just hate to have two hours of work erased in minutes. It's another tough loss. We have to start winning those close ballgames."
The Reds lineup laid the groundwork for trouble by not executing in several key situations against former teammate Edinson Volquez, who was part of the Latos trade.
Volquez threw 31 pitches in the first inning and had a whopping 57 pitches through two innings, but he largely escaped trouble all night.
Jay Bruce drew a leadoff walk in the second and scored from second base on Chris Heisey's RBI triple through the gap in right field. But Heisey would remain stuck at third base, however, as Ryan Hanigan and Latos both struck out.
In the fourth inning, Todd Frazier's one-out single put Reds baserunners on the corners and Volquez in a jam. Heisey let him off the hook as he grounded into an inning-ending 6-4-3 double play.
"We haven't been getting the big hits," Heisey said. "It's not an easy run, but it's a run I should get home. We just haven't gotten those big hits to get a rally going and get a bunch of runs on the board. We just haven't had the string of hits that we need."
Volquez, who only got better as his the evening wore on, notched a season-high 10 strikeouts and had retired nine in a row until a two-out double by Heisey in the seventh. After a Hanigan intentional walk, Volquez's career-high 127th pitch of the game induced an inning-ending fielder's choice grounder by Latos.
Latos, who was coming off of back-to-back complete game performances, gave up four hits, two walks, struck out eight and left the game with a slim 1-0 lead. If he was pumped up about facing the Padres, he did not let on.
"It's just another game," Latos said.
When Latos got an inning-ending double play from Carlos Quentin to close the sixth inning, he was cruising with only 87 pitches. He gave up ex-Red Yonder Alonso's one-out double in the seventh before escaping on a Cameron Maybin groundout to second base. Maybin appeared to be safe with a head-first slide. Cabrera struck out to end the inning on Latos' 109th and final pitch.
"I think there was a determination from both pitchers tonight that might have been a little bit different than any other game," said Padres manager Bud Black, who was ejected for arguing the call on Maybin.
Reds reliever Sean Marshall took over from Latos in the bottom of the eighth. His first batter, pinch-hitter Logan Forsythe, hit a game-tying home run to the left field seats. It snapped an eight-game scoreless streak for Marshall, who has allowed three homers in 36 games this season.
"All year, it's been haunting us -- runners on third, less than two outs," Baker said. "It really haunted again with us today. We just have to get better with runners in scoring position. What happens is you keep them in the ballgame. You keep them close, to where a solo home run ties it up. It shouldn't have gotten that far to even matter."
Brandon Phillips gave the Reds a leadoff single against Huston Street in the top of the ninth. But Phillips -- and the potential go-ahead run -- was erased on a pickoff play at first base.
"You can't win close games doing the things that we did tonight," Baker said.
Yasmani Grandal led off the San Diego ninth with a double off of the right field wall against reliever Logan Ondrusek. Alonso was intentionally walked and Maybin chopped a bunt single to the left of home plate where in an unfortunate moment, Ondrusek fielded the ball but slipped on the dirt and couldn't make the throw. That loaded the bases with no outs.
Baker summoned Sam LeCure to take over. LeCure's very first pitch was sent to the left field wall by Cabrera to end the game. With a win by the first-place Pirates, the second-place Reds have dropped to two games out in the National League Central and are only 1½ games ahead of the third-place Cardinals.
With three straight losses, the Reds have fallen to 3-5 on their West Coast trip despite getting eight straight quality starts from the rotation.
Since an 8-2 win over the Dodgers on Monday, where they were 7-for-16 with runners in scoring position, the Reds are just 16-for-94 (.170) overall in the past three games.
"The rotation, everyone, has been pitching real well. It's baseball," Latos said. "I went out there in Cleveland and gave up seven runs and the team scored seven runs to back me up. Today was a grind offensively and defensively and pitching. Things didn't go our way today."