City's victory at the KC Stadium combined with Watford's 3-2 defeat away to Peterborough leaves Bruce's side six points clear of the third-placed Hornets with four matches to play.
Substitute Robert Koren scored the Hull winner seven minutes from time after Anthony Wordsworth had cancelled out Robbie Brady's penalty.
But Bruce sounded a note of caution ahead of their game with Championship strugglers Wolves at Molineux in midweek, with Dean Saunders' side desperate for points after they lost 3-1 at home to Huddersfield.
"We've given ourselves a wonderful opportunity but you only have to look at the division's results today to realise how crazy it is," said Bruce.
"We're in a fantastic position but that's all it is and we've got another tough game on Tuesday (at Wolves).
"Wolves had a horrible result today and they'll be bang under pressure.
"We've seen before how teams at the bottom have beaten the teams at the top, because the division is so even, but it's a good position to be in.
"We can't get carried away, though. We're within touching distance but we're still got a job to do. We haven't got there yet and we've got to see it through."
Bruce singled out matchwinner Koren for praise after he headed home from close range after getting on the end of a cross from Brady.
"Sometimes Robert has his critics, which I find a bit baffling because he's scored 10 goals from midfield," added Bruce.
"He got a similar number last year and not many can do that from a midfield area.
"He's got his faults like everyone else but he's always capable of scoring a goal and you can't take that away from the kid."