The Benin international went some way towards shaking off his early-season lethargy with a stunning strike in Sunday's 3-1 Barclays Premier League victory at Fulham, just the Black Cats' second three-point haul in 19 attempts.
Sessegnon, a £6million signing from Paris St Germain in January 2011, has looked a shadow of the player he was for much of the last campaign, with O'Neill having admitted in the past that speculation that he could move away from Wearside during the summer might have turned his head.
However, the 28-year-old, who signed a new contract in August to end the rumours, showed flashes of his talent at Craven Cottage, and O'Neill is hoping his return to form will pay dividends.
He said: "He is capable of scoring more goals than he does and he himself, with that ability he possesses, should be really looking at double figures per season.
"While he sometimes maybe thinks that he is more of an assist player, I think he should be able to do some of the things that he conjured up on Sunday against Fulham."
Until Sunday, Sunderland had relied largely on £14million summer arrival Steven Fletcher to find the back of the net - indeed, until Adam Johnson struck at Everton two weeks ago, he was the only Black Cat to have registered in the Premier League this season with Newcastle's Demba Ba, whose own goal ensured a derby draw at the Stadium of Light on October 21, in second place.
The Scotland international struck five times in his first four league appearances for the club, and a run of five games without a goal coincided with their slide towards the lower reaches of the table.
But he ended his personal drought in style with a well-taken opener at Fulham, and while O'Neill was delighted to see him do so, he revealed he was happy with his frontman's form even when he was not scoring.
The Ulsterman, whose side entertain high-flying West Brom this weekend, said: "He probably will always be judged on goals as a centre-forward, that will be the first thing they would do.
"The goals he has scored for us have been very, very important, every one of them, and the goal he scored on Sunday was brilliantly taken.
"But his overall play was excellent for us and even during that time where maybe he didn't score a goal, he still led the line brilliantly.
"We need to create more chances for him, we just need to do that, to keep his goal ratio in reasonable condition. We have to do that.
"Having said that, it was also pleasing that we scored from a few other people during the course of the game, and that obviously helps confidence.
"But Fletcher has been terrific."
Fletcher's latest goal came courtesy of an inch-perfect pass from England midfielder Johnson, who continued his improvement after an impressive display at Goodison Park.
The former Manchester City man was O'Neill's other big-money buy during the summer, but a thigh injury interrupted his efforts to establish himself on Wearside as his best form eluded him.
However, the 25-year-old, like Sessegnon, has shown signs of emerging from his shell, and his manager is now anticipating big things.
O'Neill said: "He's getting a little bit of form together, which is very, very important for us and important for him as well.
"He's got the ability, we all realise that, it's just a matter of letting it come to the fore."