After throwing 13 innings without giving up an earned run in June, Niese allowed Cincinnati to jump on him early.
"You make a mistake and all of a sudden, it's 3-0, but that's just the way it went," Niese said. "I had to do my best to keep the tune of the game at that point."
The Mets struck back in the first, when Daniel Murphy and David Wright hit back-to-back doubles off Reds starter Homer Bailey to cut the lead to two, but the scoring would end there for New York.
The Mets had their fair share of opportunities early, but couldn't cash in. They squandered Scott Hairston's leadoff double in the second, stranding him at third. The outfielder had a chance to score on Josh Thole's single with no outs, but third-base coach Tim Teufel threw up the brakes. Bailey never faltered, working out of the jam by getting the next three batters.
"I got to get it going personally. First and second one out, you got to get a hit there," Thole said. "First at-bat, Scotty on base. You get a base hit, but it's just a single. I got to start driving the ball."
The Mets also had opportunities to strike in the third and sixth, but they couldn't get the hit they needed Saturday.
"We're sitting in our position today because we hit with two outs, and today we didn't," manager Terry Collins said. "We had plenty of opportunities to get back in the game. In a close game, they're going to come back to haunt you."
Zack Cozart nearly broke the game open in the fourth, when he hit a ball inches foul of the left-field foul pole with runners on second and third, but Niese battled back and kept the game within reach. He got Cozart to swing and miss on the next pitch for one of his seven strikeouts.
Niese surrendered all four of the Reds' runs over seven innings, laboring for 114 pitches, his second-highest pitch total of the season.
While the bullpen would hold it, the offense never came. Despite a .269 average with runners in scoring position on the season -- seventh-best in the Major Leagues -- New York was 2-for-11 against Bailey, who was sharp when he needed to be.
"He got strike one on a lot of guys, which all of a sudden makes you have to become alert," Collins said. "I thought he made very, very good pitches. He used his changeup very effectively. He kept his fastball down in the zone. We didn't get much good to hit."
The Cincinnati right-hander threw eight innings and issued just one walk. He did hit Lucas Duda in the sixth after Niese hit Bruce in the fourth, but Collins said he didn't think either pitcher did it intentionally.
In Friday night's 7-3 Cincinnati win, the teams traded blows at each other's superstars, with both Joey Votto and Wright each being hit by pitches. After the game, Collins said he believed the hit on Wright was intentional, but shrugged it off as a part of baseball and believed the bad blood was over.
With Saturday's loss, the Mets are 7-8 in June. They received some help from their crosstown rivals earlier in the day, when the Yankees defeated the Nationals, 5-3, in 14 innings. The Mets remain 4 1/2 games off the lead in the National League East. They're 1-3 against the Reds this season.
"Once in a while, like everybody, you catch them when they're perhaps not swinging the bats," Collins said. "That No. 3, 4 and 5 hitter in their lineup, they're about as good as anybody in the league. And they've got some other people who can do some damage, too."