Coach Andrea Stramaccioni promised a spirited response to Thursday's 3-0 Europa League reverse at Tottenham, with his pledge to steer Inter closer to Serie A's top three bringing a bumper crowd to the San Siro.
That crowd soon turned nasty as mid-table Bologna dominated from start to finish and Alberto Gilardino's classy volley midway through the second half embarrassed Inter's players into mounting a tame fightback.
Fiorentina's 2-0 victory at Lazio sees Inter slip into fifth place with AC Milan and the nearest Champions League berth four points away.
How Inter reached the interval level was anyone's guess as Bologna subjected their hosts to an unrelenting siege for 45 minutes.
The early exchanges saw Fredrik Sorensen nod a free-kick over the crossbar before Manolo Gabbiadini rippled the side netting from close range.
Former AC Milan striker Gilardino then flashed a searing half-volley across Inter keeper Juan Pablo Carrizo, who was deputising for the suspended Samir Handanovic.
It was not long before a section of frustrated home fans unfurled a banner which read: "Let one of us have a go, you never know we could be good and at least we're Inter fans..."
Nothing changed on the pitch and Alessandro Diamanti saw a dangerous free-kick skim across the goalmouth with no Bologna player able to turn the ball home.
What looked like a rare Inter foray forward ended in farce as Ezequiel Schelotto wasted Rodrigo Palacio's killer ball on the counter-attack and the whistles grew louder.
Javier Zanetti was making his 600th appearance in Serie A and not for the first time in his Inter career the Argentinian saved his club's blushes by repelling a Gabbiadini header at the back post.
Stramaccioni gave his players a dressing-down at the interval and Antonio Cassano duly replaced 18-year-old Marco Benassi for the second half.
That change paid dividends and with Inter's main creative outlet restored to the team, Dejan Stankovic soon found Juan Jesus with a deft cross, only for the Brazilian to slightly mistime his finish.
The 57th minute, however, brought the inevitable Bologna breakthrough and Jesus was a mere spectator as Gilardino volleyed Diego Perez's cross beyond Carrizo.
The Rossoblu came desperately close to a quickfire double as Diamanti beat Jesus to serve Gabbiadini from deep, but this time the connection saw the ball fly high over the bar.
With Cassano pulling the strings Inter were a different prospect, though, and the Bari-born striker was unfortunate not to tuck home an equaliser in the 72nd minute as substitute Naldo stole in to make the crucial block.
It was a rare moment of brilliance from the hosts but Bologna were dangerous every time they went forward and Carrizo was at full stretch to repel Rene Khrin, who wriggled free to get his head to Diamanti's corner.
Time was running out for Inter and not even an acrobatic bicycle kick from Andrea Ranocchia five minutes from time could save them from defeat in front of a disillusioned home crowd.