The Sunderland loanee has not scored in his last 21 games, spanning across three clubs - Swansea, the Black Cats and now Hull - and he was wildly off target in a 1-1 draw with Malky Mackay's men at the KC Stadium.
He smashed over the bar of an open goal from eight yards with six minutes on the clock and then ended the game with a poor miss with a header which barely tested Joe Lewis in the Cardiff goal.
The 28-year-old last scored a goal of any description in Swansea's Capital One Cup win over Chelsea on January 9, but manager Bruce is not ready to give up on the player who Sunderland paid £6million for just a matter of months ago.
"He has got to stay at it," said Bruce, who, aware of Hull's anaemic front line, made a late and ultimately unsuccessful deadline-day move for West Brom's Shane Long.
"Danny has to stay strong. I just spoke to him about that. If you're a striker, you go through these spells. You don't lose your ability, but you have to stay strong. That's the Premier League, it's tough.
"I'm not going to single anyone out. A striker is judged on goals. He's finding it difficult but perhaps that's why he's here. He needs one to settle him down. Perhaps he's trying too hard because his overall game was terrific. He needs one to go in off his backside.
"Who knows, he could go and score the winner against Newcastle next week."
There would be a certain irony to that for Graham is a lifelong Newcastle fan, although Hull need the goals to come from anywhere they can get them.
Last year's elevation from the Championship was in spite of their forwards rather than down to them and a lack of final-third punch was clear again.
After taking the lead through defender Curtis Davies' first goal for the club - a smart 40th-minute header off Tom Huddlestone's inviting cross - Hull went into their shells somewhat and were made to pay when Peter Whittingham equalised after the break.
The midfielder's close-range volley did prod the home side back into life but with striker Graham so out of form, they were unable to regain their advantage.
"I'm not just blaming the strikers, it's as a team. When we create the chances we do, it leaves a bad taste," Bruce added.
"I said last season that chances were our Achilles heel and with the ones we created we could have easily won the game.
"At this level you don't get chances too frequently and we have to improve on that."
For Cardiff, the result brought about a first point on the road since their promotion as champions and continued their impressive adjustment to life in the top flight.
Since a 2-0 loss at West Ham on the opening day they have gone three unbeaten, including a fine win over Manchester City.
Despite the chances Hull created, few could suggest Cardiff were not deserving of a point, as their passing was crisper and in full-back Kevin Theophile-Catherine they had the game's outstanding performer.
"We both time had time on the ball, both tried to win and had chances other than the goals."
While Graham's misses were notable, so was Aron Gunnarsson's failure to make the most of a near-post header from a Theophile-Catherine cross shortly after the goal.
"Aron said he should have scored but the flip side is Danny Graham would maybe say the same," Mackay added.
"Hull have a manager I know well, an excellent manager and I knew it would be tough and it proved that way. We deserved a point.
"We have character and resilience and twice now we have come from losing positions to get something.