Plawecki drove in one and scored the go-ahead run, leading to a 3-1 win over the Augusta GreenJackets at Lake Olmstead Stadium.
The Sand Gnats have won two of the first three games in the four-game series. The GreenJackets lost for just the second time in the past seven games.
Plawecki, a first-round pick in 2012 out of Purdue, went 2 for 2 with one RBI and was hit by a pitch twice, upping his average to .364.
“The kid got smoked twice tonight,” GreenJackets manager Mike Goff said. “He’s a good kid, plays hard, stayed in the game and I respect him for that.”
Sand Gnats starter Matt Koch allowed one unearned run on four hits in six innings, walking one and striking out five.
Koch entered the game with a 231/3-inning streak of not issuing a walk. The streak ended at 28 innings on a two-out base on balls by Stephen Branca in the fifth.
GreenJackets catcher Eric Sim went 2 for 4 with a double. Augusta (24-17) recorded eight hits but left six on base.
“We continued to take the fastball away and got in holes,” Goff said. “We made no adjustments tonight whatsoever.”
Augusta starter Matt Lujan went 32/3 innings, allowing one run on seven hits with no walks and two strikeouts. Goff said he was on a pitch count of 70, which he reached in the fourth inning.
Augusta started the scoring in the first inning with a run on a groundout by Joe Rapp. Savannah (23-17) tied the game in the fourth on an RBI single by Plawecki.
In the sixth, Plawecki reached on a hit by pitch, advanced on an error and scored on a wild pitch. The Sand Gnats added an insurance run in the eighth on an RBI single by Cole Frenzel.
The GreenJackets put runners on in six innings but reached third base just twice. Sim represented the tying run on third base in the seventh, but a strikeout and groundout stranded him. They stranded two in the ninth.