Villa's bid to secure England's fourth Champions League place has hit the buffers in recent weeks, with just one point collected from a possible 15.
O'Neill's side, whose next two league games are at Liverpool and then Manchester United, are also without a win since 7 February when they beat Blackburn 2-0 at Ewood Park.
O'Neill disappointed with second-half display
Despite that woeful run, O'Neill believes Villa can pip Arsenal to fourth.
"In November we lost two games in six days and then went on a 13-match unbeaten run," he said.
"We probably have to get something from the next two games which will be pretty difficult, but I believe it is possible that we can still fight back, and the players feel that, too."
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