Johnson returned early from international duty in September with a thigh injury which has hampered his efforts to establish himself at the club which invested £10million in his services. However, his strike at Everton last weekend, which ultimately counted for little other than his personal development after the Toffees staged a fightback to win 2-1, has lifted his mood and O'Neill is now looking for him to show more as he prepares for Sunday's Premier League trip to Fulham.
He said: "Scoring the goal was very, very important. I don't care who you are, the very, very best players can lose confidence, but eventually, if you feel as if you have the talent, you should pull through. "How you do that is either getting down to doing things more regularly in training - there's always a possibility of being able to resolve it then - but the confidence really comes from performing on the field. "I have said this before and it's almost as if it's a recurring theme, but players who are confident and who can make things happen when they are confident, it's a major boost to them when they feel as if they are capable of doing it."
Sunderland head for Craven Cottage in the midst of a frustrating run of results which has left them just three points clear of the relegation zone. They have won only one of their last 18 league games dating back to March, although the defeat at Everton was just their third of the current campaign. A return of nine points from 10 games is significantly less than they might have hoped for, but O'Neill, while recognising that their tally needs to start ticking over rather more quickly, insists there is no real cause for concern. He said: "There are a group of teams gathered where there is not a great deal of points differential.
"But we can talk about it every single week here - we need to win some football matches and the sooner we do that, the better. "We have to look at points on the board now at this stage and start galvanising ourselves." Sunderland will arrive in London to face a Fulham side which has registered creditable draws against Everton and Arsenal in its last two games, and for whom striker Dimitar Berbatov has proved a shrewd acquisition.
O'Neill said: "They are a good side - they have been a good side now for some time. They have a settled nucleus of the side, and then they have been able to bring in some really decent players. "The loss of [Clint] Dempsey or [Mousa] Dembele this season, who have been major players for them, they seem to have covered it up reasonably well at this minute, and of course the addition of Berbatov has given them a goalscoring threat.
"He is playing very, very well. He's a top-quality player - he cost Manchester United £30million a few season ago. "He was unable to stay in the side long enough, but look at the competition Manchester United have there. The move away from Old Trafford looks as if it has re-invigorated him." O'Neill has injury concerns over Keiren Westwood, Phil Bardsley, Lee Cattermole and Steven Fletcher, but will be able to call upon winger James McClean, who hit the headlines once again at the weekend because of his decision not to wear a Remembrance Day poppy on his shirt at Everton. O'Neill said: "James wasn't aware until very late on that there was going to be a poppy worn. It was his choice not to do it, of course, and I have empathy with that knowing his background. "It's a choice. Does not wearing a poppy make him feel any differently about the situation? You would have to ask him that."