The Black Cats drew for the sixth time this season as both sides failed to find the net at the Britannia Stadium.
"I think that we're getting stronger," O'Neill told Sky Sports News. "Although we've drawn quite a number of times, we've only had the one defeat this season and eventually you would need to turn a couple of draws into wins. But I'm hoping in the near future that we're able to do that."
The point from Saturday's stalemate has left Sunderland in 14th place in the Premier League table.