The Tigers stretched their unbeaten run to five games with a comfortable victory over Brentford that may well go a long way towards securing home advantage in the semi-final second leg.
Hull, thanks to a goal difference that is now seven superior to nearest rivals Derby, realistically need just one more win from the final two games to guarantee fourth place.
That may come as early as Saturday, when a trip to rock bottom Bolton Wanderers awaits.
Considering there were concerns just a few weeks ago that Hull, then mired in a dreadful run of results, might miss out on the top six altogether, it represents a decent recovery and points to a side ready to make a serious push for the Premier League.
What Harlee Dean’s own goal and Mohamed Diame’s eighth strike of the season also did was ensure a happy end to a night on which the 15,225 crowd had made clear their displeasure at the club’s planned new membership scheme.
Around 8,000 red cards were held up ahead of kick-off by fans unhappy with the plan to replace season tickets for 2016-17.
The scrapping of concessions for children and senior citizens has caused much of the ire felt by supporters, along with many having to relocate seats to take advantage of the cheaper prices.
For the opening half hour, the protest – literally showing the red card to the new scheme – had been just about the most noteworthy part of the evening.
Hull’s seven changes to the side that had drawn 2-2 against Leeds United played a part, Bruce’s intention to give the likes of Isaac Hayden, Alex Bruce and Adama Diomande much-needed time on the pitch ahead of the play-offs leading to a disjointed start.
That was, however, until Harry Maguire, the game’s standout performer, produced a quite superb 50-yard crossfield pass that allowed Andrew Robertson to control with his chest and dart into the penalty area unchallenged.
Having reached the byline, the Hull left-back drilled in a cross that, in trying to avert the danger, Harlee Dean could only turn into his own goal.
It was just the fillip the Tigers needed and their advantage really should have been doubled just five minutes later.
A tug on Bruce as the Bees tried to defend a corner sent the defender sprawling and referee Darren Bond pointed to the spot.
Diomande stepped up only to see his penalty brilliantly saved low to his right by David Button.
It was a let-off for the London club, who had another big escape shortly afterwards when Robertson, again having got in behind the defence courtesy of his searing pace, hit a ferocious left-foot shot that crashed against the crossbar and to safety.
Hull may have been frustrated by being denied twice in quick succession, but they got the all-important second goal on the stroke of half-time.
More enterprising play by Maguire, this time involving a charge down the right flank and incisive cross, created the opening for Mo Diame.
Button did manage to block the Senegal international’s first effort but he would not be denied as the ball was forced over the line.
Brentford, play-off semi-finalists last season, had arrived in the East Riding on the back of a fine run that had yielded 16 points from their previous half a dozen outings.
It was difficult to see how on last night’s display, the Bees being distinctly second best to their hosts once that largely flat opening half hour was out of the way.
Dean Smith’s side had a couple of first-half efforts that flew well wide.
Eldin Jakupovic, making his first league start in 18 months, also had to show safe hands when dealing with Marco Djuricin’s shot early in the second half but, otherwise, the Tigers were rarely troubled.
Bruce’s side always looked the more likely to add a third, but Sam Clucas curled a free-kick over the wall that Button did well to hold and Chuba Akpom headed wide as the hosts cruised to all three points.
Hull City: Jakupovic; Odubajo, Bruce, Maguire, Robertson (Maloney 68); Elmohamady, Hayden, Livermore, Clucas; Diame (Taylor 83), Diomande (Akpom 78). Substitutes (not used): McGregor, Taylor, Davies, Huddlestone, Snodgrass.
Brentford: Button; Clarke, Barbet, Dean, Bidwell (O’Connell 72); Canos (Saunders 81), Yennaris, Woods, McCormack, Swift (Gogia 61); Djurcin. Substitutes (not used): Bonham, Colin, Hofmann, Kerschbaumer.
Referee: D Bond (Lancashire).
Results and tables: Page 24.