Arcobello was called for cross-checking at the end of the second period, then with just 25 seconds left in the game, drew a tripping call that likely prevented a Rampage empty-net goal.
“You don't want to take penalties, but they happen,” Helmer said. “We took a couple there that weren't real smart.”
San Antonio (28-22-2-1) got on the board just more than seven minutes into the game when Michal Repik took advantage of a Barons giveaway. Oklahoma City goaltender Yann Danis stopped Repik's initial shot but failed to negate Repik's attempt off the rebound.
“He was our best player tonight,” Nelson said.
He declined to elaborate on any other players' performance.
“I don't want to say anything I'm going to regret,” Nelson said.
The Barons host Texas at 7 p.m. Wednesday in the last game of a four-game homestand before going on the road for six consecutive games.