AC Milan lost further ground in the Serie A title race as they were held to a goalless draw by Atalanta at San Siro on Saturday.
Monday's defeat to Roma saw Luciano Spalletti's side move three points clear in second, with leaders Juventus a further four points in front.
But third-placed Milan proved unable to bounce back with a victory ahead of a clash between the top two later on Saturday.
Milan had failed to score in three of their last four home league clashes with Atalanta prior to this latest meeting and it was the visitors who posed the biggest threat in the first half, with the exception of a Luca Antonelli effort that hit the post.
The hosts were much improved after the interval but failed to make the breakthrough that would have turned up the heat on Roma ahead of their trip to Turin.
The first half was played out under a blanket of thickening fog, with clear-cut goalscoring opportunities initially in short supply.
Andrea Petagna - Atalanta's biggest threat - fired wide from 25 yards in the early stages, before captain Alejandro Gomez fired across the face of goal when attempting to beat Gianluigi Donnarumma from a tight angle.
Despite Milan edging possession, it was Atalanta who looked more dangerous as the opening period progressed, and Petagna will feel he should have done better when he poked wide having barged his way through the home defence on the half-hour mark.
Andrea Conti then headed just over from a Leonardo Spinazzola cross, before Donnarumma denied Roberto Gagliardini from close range.
The half looked set to finish without Milan having made a single attempt on goal until the advancing Antonelli rifled an effort against the left-hand upright in the closing seconds.
But Milan were immediately under pressure at the start of the second half when Andrea Bertolacci was robbed of possession by Conti, but Gomez failed to get a shot away after working his way into the box.
Former Atalanta man Giacomo Bonaventura's magnificent turn on the edge of the area deserved a better finish than his smash over the crossbar, but he came closer just a few minutes later when he fizzed a low drive just wide of the right-hand post.
Milan grew in confidence and dominated the latter stages, but Gianluca Lapadula was unable turn the ball into the net after goalkeeper Marco Sportiello carelessly rushed a long way off his line in an attempt to gather.
Juraj Kucka then danced around his marker - and through the lingering fog - only to fire well wide, before Donnarumma was called into action to palm over a looping Rafael Toloi header.
Carlos Bacca came close to snatching the points seven minutes from time, but Conti was on the line to keep him out and preserve parity.