O'Neil said: "It was a good performance, the scoreline probably doesn't tell the full story. We were very comfortable for long periods and we probably should have put it to bed.
"We know Luton are a threat from corsses and set-plays and we had to suffer a nervous few minutes at the end.
"It's amazing the difference having a couple of attackers makes to us. It is the first time since 30 December that we have been able to name Hwang (Hee-chan) and (Matheus) Cunha in the same team. We've had a tough spell without them, although they aren't fully fit at this moment they are big for the group.
"We've got a talented group but it's difficult to always be a threat without attackers. We can have the ball, think back to West Ham when we dominated possession, but we can't always make it count without the right attackers.
"There are so many positives from this season. We've improved on the points tally of last year, stabilised the club financially and I think it's 13 academy players involved in matchday squads."