In his fourth start for Atlanta, Gausman (8-9) gave up four hits with five strikeouts and two walks, helping the NL East-leading Braves take the first two legs of the three-game series. He has allowed six runs in 27 innings since being acquired from the Baltimore Orioles on July 31.
"This is a fun team to play for, especially right now," Gausman said. "We're playing well and it's a fun place to come to work every day. A little different than where I've been this season. It was frustrating being over there, being a part of the season (the Orioles are) having over there was tough."
Swanson's first homer gave the Braves a 2-0 lead in the fifth before he sent another two-run shot into nearly the same spot in the left field bleachers, extending the lead to 5-0 in the seventh. Kurt Suzuki doubled down the left-field line, scoring Ozzie Albies from first for the third run. Tyler Flowers scored on a wild pitch in the ninth to make it 6-0.
"You're not really looking at the results," Swanson said. "You're really looking at the progress and the process. ... It's definitely a good thing moving forward, but tomorrow's a new day."
Ivan Nova (7-8) allowed Swanson's first home run after retiring his initial 10 batters, including the first nine on 29 pitches. Ender Inciarte singled to center for Atlanta's first hit with one out in the fourth.
Nova got through six innings on 78 pitches (51 strikes), but was removed when Josh Harrison pinch-hit with one out and the Pirates trailing 2-0 in the sixth. He allowed two runs and four hits with four strikeouts.
The Pirates had allowed one run in each of their previous five games, but were 2/3 during that stretch.
"I knew (getting pulled) was going to happen," Nova said. "We need to score. It's been tough the last week. A lot of good pitching."
Harrison singled and the Pirates eventually loaded the bases with two outs, but Gausman got out of the jam when Josh Bell grounded out to short.
"(Gausman) is pitching exactly how we had hoped when we got him," Braves manager Brian Snitker said. "He was really, really good tonight. That was huge."
"Can we adjust the lineup, look at some different things? We've talked about it," Pirates manager Clint Hurdle said. "It's been hard. These guys are battling. Guys are doing some different things to try to change up some things. ... We're not getting the results we want."
Braves: OF Michael Reed was recalled from Triple-A Gwinnett. RHP Bryse Wilson was optioned to Gwinnett following his major league debut Monday.
Pirates: RHP Clay Holmes was recalled from Triple-A Indianapolis. OF Jordan Luplow was optioned to Indianapolis.
Braves: Suzuki was pulled after being hit by a pitch in the ninth inning. Flowers ran for Suzuki shortly after he made his way to first base. Snitker did not provide an update following the game.
Pirates: OF Starling Marte did not start after visiting a doctor for undisclosed reasons earlier Tuesday. He entered the game as a defensive replacement in center field for the eighth inning. Marte was benched Monday, but pinch hit in the ninth inning after Hurdle deemed he lacked effort while running the bases in a 2-1 victory over the Chicago Cubs on Sunday.
Braves: RHP Julio Teheran (8-7, 4.24) would like to build off his past two starts when he takes the mound for the series finale against the Pirates on Wednesday. After failing to go at least six innings in three starts from July 24-Aug. 5, he has gone a combined 13 in his last two starts while allowing three runs and five hits.
Pirates: RHP Trevor Williams (10-9, 3.53) will aim to keep his hot stretch going when he faces the Braves on Wednesday. He has allowed two runs or fewer in each of his past six starts and hasn't surrendered a run in four of those starts, dating to July 11.
More AP MLB: https://apnews.com/tag/MLB and https://twitter.com/AP-Sports
Judge rules Lorena Martin, Seattle Mariners must go to arbitration
Lorena Martin's wrongful termination lawsuit against the Seattle Mariners must be resolved in private arbitration rather than in court following Friday's ruling by a judge in King County (Washington) Superior Court.
Regular-season pitch clocks this year are a real possibility
Major League Baseball announced the parameters for a 20-second pitch clock for spring training games Friday, and sources told ESPN that adding it for this regular season is a real possibility.
Machado: I like what the Padres bought to the table
Manny Machado is looking forward to playing for the Padres and helping out their young core.
10 stars not named Bryce or Manny who changed teams this winter
From Paul Goldschmidt in St. Louis to Josh Donaldson in Atlanta, we tell you what to expect from some familiar faces in new places.
Buster's Buzz: Why Nationals' defense will be much better in 2019
While the potential loss of Bryce Harper could be a big blow to Washington's lineup, an offseason defensive overhaul might be the difference-maker in a tough National League East fight.
What we're excited to see now that spring training games are here
The long offseason wait is over -- let the games begin! -- giving us a chance to focus on what will happen between the lines.