Chris Thorburn scored for the Jets, who have lost three straight.
Edmonton erased a 1-0 deficit 2:39 into the second period when Tyler Pitlick put the puck in front of the net for a hard-charging Joensuu to direct past Jets goalie Edward Pasquale. It was Joensuu's third goal of the preseason.
The Oilers then took the lead at 9:22 of the second, when Acton deflected an Anton Belov point shot through Pasquale's legs.
"My focus has been to take care of my game every day and hopefully the rest takes care of itself," Acton said.
Both teams finished 0-for-7 on the power play.
"There was a lot of special teams," Jets coach Claude Noel said. "Our penalty kill was decent. I didn't think our power play was very cohesive. I didn't think we moved the puck that great. It was kind of a scrambly game. On our part, we didn't generate a lot of offense. It was a tough night for us."
Material from wire services was used in this report.
|Grant Clitsome Kneeing - 2 min against Andrew Ference|
|Andrew Gordon Charging - 2 min against Andrew Ference|
|Boyd Gordon Interference - 2 min against Jacob Trouba|
|Evander Kane Hooking - 2 min against Andrew Ference|
|Taylor Fedun Hooking - 2 min against Olli Jokinen|
|Ladislav Smid Roughing - 2 min against Chris Thorburn|
|Mark Stuart Slashing - 2 min against Tyler Pitlick|
|Olli Jokinen Interference - 2 min against Mark Arcobello|
|Patrice Cormier Hooking - 2 min against Linus Omark|
|Mark Arcobello Tripping - 2 min against Matt Halischuk|
|Nick Schultz Holding - 2 min against Andrew Gordon|
|Philip Larsen Tripping - 2 min against Evander Kane|
|Mike Brown Roughing - 2 min against Evander Kane|
|Evander Kane Roughing - 2 min against Mike Brown|
|Nick Schultz Hooking - 2 min against Olli Jokinen|
|Jacob Trouba Hi-sticking - 2 min against Ladislav Smid|