Mauro Icardi wasted a glorious stoppage-time chance as Inter missed the opportunity to put further distance between themselves and city rivals AC Milan in the race for Champions League qualification with a 0-0 draw at San Siro.
Having looked likely to win Derby della Madonnina for a second time this term, Luciano Spalletti will know Inter should have more than a two-point cushion over fifth-placed Lazio.
The scoreless draw was enough to maintain their eight-point advantage over Milan, meaning Lazio are now the main side who can deny them a return to Europe's top club competition.
Icardi, scorer of a sublime hat-trick that gave Inter a 3-2 win in the teams' last league meeting, appeared to have scored what would have been the decisive goal late in a frenetic first half, only for the VAR to rule him offside.
Leonardo Bonucci and Patrick Cutrone did force Samir Handanovic into a pair of smart saves either side of half-time but, in truth, the Rossoneri struggled to carve out the clear openings required to close the gap.
And they should have been punished by the normally reliable Icardi, but with the goal gaping on two occasions he somehow managed to miss the target, leaving a frustrated Inter to settle for a point.
5 - Inter have kept the clean sheet in five Serie A consecutive matches for the first time since August 2005. Wall. April 4, 2018
The raised stakes of an encounter Gattuso described pre-match as being "back to something significant" were evident from the intense early exchanges as Franck Kessie got in the way of Rafinha's third-minute shot.
Gianluigi Donnarumma was then forced to parry a stinging Antonio Candreva effort, while Marcelo Brozovic twice curled harmlessly wide either side of that attempt.
Inter's early momentum would have been completely erased if not for the incredible reflexes of Handanovic, who somehow clawed Bonucci's flick-on header away the bottom right corner.
Far from assured at the other end, Milan were fortunate that Ivan Perisic's loose touch cost him a better sight of goal midway through an entertaining half.
And they earned another reprieve when the VAR deemed Icardi to have marginally strayed into an offside position prior to firing in what looked to be the opener.
0 - The Milan Derby haven't seen any goal in the first half of a Serie A match for the first time since September 2015. Caution. April 4, 2018
The Rossoneri started the second half in the same unconvincing manner as the first, Donnarumma seeing a Perisic cross drop on top of his crossbar before a tame Brozovic strike squeezed through the young goalkeeper's fingers.
It was yet to become one-way traffic, though, with Handanovic's smother from Cutrone in the 52nd minute a reminder of the delicate scoreline.
Earlier denied by an offside decision, the assistant's flag - albeit contentiously raised - spared Icardi from complete embarrassment prior to the hour after he somehow transpired to screw Candreva's squared pass wide of an empty net.
Cutrone also had an impressive bicycle kick correctly ruled out as the tension increased with the clock ticking into the final 20 minutes.
There was still time for Icardi to go agonisingly close in the 93rd minute, but the skipper's outstretched boot could only turn Joao Cancelo's low cross inches around the around upright, denying Inter a result that would have moved them third.
