Matt Taylor inflicted upon Hull a third successive defeat, but it was Bolton goalkeeper Jussi Jaaskelainen who emerged his side's real hero in the 1-0 result.
For the first time since mid-April, Bolton manager Gary Megson can reflect on back-to-back victories after Taylor's 50th-minute half-volley separated the sides.
However, such a feat would not have come about but for Jaaskelainen, who produced a virtual one-man show for the remainder of the half to frustrate all connected with the Tigers.
After defeats by Chelsea and Manchester United that had seen City slip from its previously lofty third-placed perch, this was always going to be an acid test of its Premier League credentials.
From this latest loss, the critics will now expect Hull to go into freefall and fight the relegation battle that was expected of it at the start of the season.
But this was one of those freaky results as Hull could have played on into the night and not beaten Jaaskelainen, when on another day it would have won by three, four, maybe five.
Against a Bolton side revitalised by a 2-0 home win over Manchester City last weekend, Hull controlled a first half in which goalkeeper Boaz Myhill barely touched the ball.
There was one anxious moment when he and Paul McShane failed to make a decisive call on a loose ball running out of play.
That allowed Ricardo Gardner to chase what was initially a lost cause, ultimately turning the ball into the six-yard box.
Gardner's energy aside, there was no support, despite Megson opting to unusually play two up front away from home as he paired Kevin Davies and Johan Elmander in attack.
Davies wore the skipper's armband in the absence of the suspended Kevin Nolan, whose influence was sorely missed, while Elmander was back in the side after recovering from a groin strain.
Instead it was Hull who always had the edge as it probed down the flanks, and through the industrious Geovanni there was always an outlet.
It was his 13th-minute shot from 25 yards that Jaaskelainen was forced to smother low down to his left-hand post.
The Brazilian then provided a 19th-minute cross from the left wing into the heart of the area, where Marlon King showed considerable ingenuity.
Rising for the ball, but with his back to goal, King caught it with his right backheel and then agonisingly saw it clip the crossbar.
Daniel Cousin was also a whisker away in the 31st minute when he attacked a left-wing ball with his head, this time from George Boateng, only for it to drop inches wide of the left-hand post.
It was then sod's law that after doing nothing in the first half, Bolton managed to take the lead five minutes into the second.
Gavin McCann delivered a corner into the near post that was met by a looping header from captain Ian Ashbee that came off the back of Gretar Steinsson.
The ball then sat up for Taylor to strike a half-volley from the edge of the area that crept inside Myhill's right-hand post, much to his fury and frustration.
The reason Hull then failed to equalise was down to Jaaskelainen as he stole the spotlight.
A foul from Fabrice Muamba on Dean Marney gave Geovanni the perfect opportunity from 22 yards, but despite looping a right-foot shot over the wall, a full-stretch Jaaskelainen clawed the ball away.
Then in the 70th minute,