Then again, it's not that surprising. The four-time All-Star has turned in stellar outings before.
Outdueling Nationals starter Edwin Jackson (5-6), Sheets (2-0) extended his scoreless innings streak to 12 in his return after missing last season because of Tommy John surgery on his right elbow. The victory pushed the Braves' winning streak to three and moved them within 1½ games of the NL East-leading Nationals.
"It's been a huge pickup for us," McCann said of adding Sheets to the Braves rotation. "To come out here for his two starts and pitch the way he has. Hasn't given up a run, he's pounding the zone and the more you're around him the more you know why he's so successful. He's a competitor, he knows what he's doing."
The Nationals have lost three straight, including the series opener Friday night, blowing a 9-0 lead before falling 11-10 in 11 innings.
Washington removed Bryce Harper from the game after two innings with a left ankle bruise. The 19-year-old fouled a bunt off his left ankle. X-Rays were negative, and the rookie outfielder didn't start in the second game.
McCann's solo homer in the second inning, his 16th of the season and seventh in his last 10 games, gave the Braves their first run. Atlanta added another in the eighth as Michael Bourn scored on a wild pitch by reliever Henry Rodriguez.
Jones, entering as a pinch hitter in the ninth with a runner on, clobbered the first offering from Ryan Mattheus over the right field wall.
In his second start of the season and with light rain falling intermittently, Sheets threw 91 pitches, allowing five hits with six strikeouts and three walks.
"If you're asking me if I'm surprised I haven't given up a run, yeah," Sheets said. "I'm not surprised that I'm getting people out. I wouldn't have come back if I didn't think I could get anybody out."
The Nationals put runners on in five of the opening six innings. Three times, they had two men on base, but could not capitalize.
Sheets threw a fastball past LaRoche, striking out the slugger with two on to end the first. With runners on the corners and one out in the third, he induced Morse into a double-play grounder.
After allowing a single and a one-out walk in the sixth, the 33-year-old nimbly recorded the final two outs, including another strikeout of LaRoche.
"I had a couple of chances to drive some guys in," said LaRoche, who denied any carryover factor from Friday's stunning loss. "(Morse) hits a ball on the screws into a double play. One of those nights, just didn't get enough going."
Jackson struck out nine to match his season high while allowing five hits and two walks over seven innings. His one mistake: McCann's homer as the high drive landed over the right-center wall. The Braves catcher has homered in three straight games.
"Once I found it, I knew," McCann said of his recent power surge and 11-game hitting streak. "I haven't felt like this since 2008, really."
Harper's failed bunt attempt came in the bottom of the first inning. Limping and doubled over in pain for several moments, the first time All-Star completed the at-bat by striking out. Harper returned to center field in the second inning, but Roger Bernadina replaced him on defense for the top of the third with the Nationals trailing 1-0.
Bourn finished with two of the Braves' nine hits and had two stolen bases. He swiped third as the front end of a double steal in the eighth inning before scoring on the wild pitch.
Bernadina had two hits and threw out Paul Janish attempting to move from first to third on Michael Bourn's one-out single in the fifth.
The opening game was a makeup of a June 1 rainout. Considering the Braves recent run, one might call the timing of the makeup fortuitous.
"Certainly last night's game you chalk up as a fluke because that doesn't happen very often," Jones said of the nine-run rally. "But to back it up with a solid performance today, now we get some momentum going. I can't think of a better day to have a doubleheader, as nice a roll as we're on."
Braves second baseman Dan Uggla finished 0 for 4, all on strikeouts, three coming against Jackson. ... With two RBIs, Jones has 1,600 for his career. ... Nationals OF Stephen Lombardozzi and Braves 1B Freddie Freeman had their hitting streaks end at 13 and 11 games, respectively. ... The Braves recalled RHP Randall Delgado to start the nightcap of Saturday's doubleheader against John Lannan, making his 2012 debut.