A steamy day at Citi Field turned into a painful one for the New York Mets when their top two hitters went down with injuries.

Jose Reyes tweaked his troublesome hamstring again and Daniel Murphy was helped off the field with a throbbing knee injury during a 6-5 loss to the Atlanta Braves on Sunday.

"We've been struggling offensively as it is. Now we lose a guy hitting .335 and another guy hitting .320, obviously that's going to be difficult to overcome," said third baseman David Wright, who found himself filling in at shortstop for the first time in his major league career. "We know it's going to be a tremendous uphill battle to try to score runs."

Longtime nemesis Chipper Jones hit a tiebreaking single off Bobby Parnell (3-4) in the ninth inning and Atlanta handed the depleted Mets their sixth loss in seven games.

After almost 3½ hours of back-and-forth baseball, it was a difficult defeat to endure.

"It felt like it was about a 12-hour game," said rookie Justin Turner, who went from second base to shortstop and back to second base. "We felt like we literally just walked off a battlefield, with the heat and all the switching around and the grinding and coming back and tying it up. It's tough, mentally and physically."

Jason Heyward, Alex Gonzalez and Jose Constanza homered early for the Braves, who finally solved New York rookie Dillon Gee. Dan Uggla extended his career-best hitting streak to 28 games.

Gee entered 2-1 with a 1.52 ERA in four outings against Atlanta, including two wins and a 0.54 ERA in three starts this year. He was originally slated to start Wednesday night against Florida, but that game was rained out.

"I'm just really disappointed. Obviously, I didn't get the job done," Gee said. "I hate to see Parnell come in and get a loss for a game that I really lost. I never really gave us a chance today."

It was the first major league homer for Constanza — he also got his first stolen base, spiking Murphy hard in the process on a clean but awkward play.

Mets general manager Sandy Alderson said Murphy has a substantial injury to his left knee and will be placed on the disabled list.

Reyes, the NL batting leader, was lifted in the second because of a stiff left hamstring, the same spot that landed him on the DL last month.

Alderson said he thought Reyes hurt himself running out a first-inning grounder and it appears he has a mild hamstring pull, the same injury that cost him more than two weeks in July.

X-rays on Murphy's leg were negative, but the team was waiting for MRI results on both players. The Mets, who traded Carlos Beltran in late July, are also missing injured first baseman Ike Davis.

"We're not going to stop the focus, we're not going to throw our hands up," manager Terry Collins said. "We're going to find somebody to come in and play some spots, and with that there will be expectations of people that are going to fill in there."

Jason Bay had three hits, three runs and a stolen base for New York during a perfect day at the plate. He singled leading off the ninth but was erased when he ran into a tag on Angel Pagan's double-play grounder.

After a walk, closer Craig Kimbrel retired Nick Evans on a grounder for his 34th save in 39 chances. A fired-up Jones pumped his fist emphatically after making the throw from third to end it.

"It was a good win for us. We needed it. Badly," he said.

A humid, 86-degree day in Queens turned sour when Reyes and Murphy got hurt. New York made three errors and lost two of three in the series against the NL wild card leaders.

Jonny Venters (6-1) worked a hitless inning for the win.

Braves lefty Mike Minor was called up from Triple-A Gwinnett for the fourth time this season to start in place of injured All-Star Jair Jurrjens, who went on the 15-day disabled list Saturday because of a strained right knee.

Minor left with a 5-2 lead and two outs in the sixth, but the bullpen couldn't hold it.

Murphy entered as a pinch-hitter and drove in a run with an infield single, a dribbler up the third base line. Willie Harris cut it to 5-4 with an RBI single.

Bay scored the tying run in the seventh when left fielder Martin Prado missed an attempt at a sliding catch, misplaying Pagan's sinking liner into an RBI double.

After his RBI single, Murphy stayed in the game at second base — but didn't last long.

Constanza's foot popped up off the bag when he slid hard into second and came down on Murphy's prone left leg, between his ankle and knee. The lower portion of Murphy's leg was driven awkwardly toward the ground, and he hobbled away immediately in pain.

Murphy, out of the majors in 2010 because of two right knee injuries, stayed down in the outfield for a while before he was helped off the field.

"He was in a lot of pain. He just said, 'Get me off the field,' that's all he kept saying, 'Just get me off the field,'" Collins said.

Constanza also was shaken up on the play, but remained in the game.

The injuries forced Collins to get creative with his defensive alignments. In the seventh, he moved outfielder Scott Hairston to second base. By the eighth, Hairston was back in right field and Wright was playing shortstop.

NOTES: SS-2B Ruben Tejada will be recalled from Triple-A Buffalo to take Murphy's spot on the roster. Alderson said the Mets would wait and see about Reyes' injury before deciding if another roster move is needed. ... New York begins a four-game series Monday night against San Diego, with Mike Pelfrey on the mound.