It was the ninth straight loss for the Tigers, who will close their disappointing season with game three of the series vs. the Razorbacks, who improved to 37-17 overall and 17-12 in the SEC.
Auburn fell to 22-33 overall and 9-20 in the SEC. The losing streak is Auburn's longest since the 2001 season.
The hosts chased Auburn starter Evan Crawford in the third inning. The freshman pitcher gave up nine hits and six earned runs.
The Razorbacks got a single run in the first, two in the second and added three in the third inning to take charge with a 6-3 lead and were never seriously threatened after that.
Arkansas increased the lead to 8-3 with single runs in the fourth and sixth innings before Auburn cut the gap with a pair of runs in the seventh. However, the Razorbacks matched that with two runs in the bottom half of the inning.
"Every time we made a push, they answered right back," said Auburn coach Tom Slater, who noted that his starting pitcher, Crawford, wasn't his normal self due to tightness in his lower back. "He's a tough, tough kid," the coach said.
Auburn scored its first run in the second inning on a two-out double by Edwards to drive in Russell Dixon, who reached base on a single.
The Tigers added a pair of runs in the third inning when Luke Greinke smacked a two-run homer with Johnstone on board. Johnstone led off the inning and reached base on an error.
The Tigers added two more runs in the seventh. Edwards got one with a solo homer. Johnstone, who reached on a single, scored the other run on a single by Andy Bennett.
Brett Butts pitched 4 1/3 innings of relief for the Tigers and gave up two earned runs on five hits.
Johnny Thompson finished the game on the mound for Auburn. He allowed just one hit without a run in 1 1/3 innings.
Daryl Maday got the win pitching five innings. He gave up three runs on five hits.
James Ewing led the Razorbacks at the plate. The second baseman banged out four hits and scored twice while driving home two runs.
Auburn will send Chris Dennis to the mound for Saturday's game that is scheduled to start at noon.