Romelu Lukaku was Inter's hero, converting an injury-time penalty for his second goal of the game as Antonio Conte's men came from behind to beat Bologna 2-1 at Stadio Renato Dall'Ara.
Despite enjoying the better of the first half, title-chasing Inter looked set to drop points when Roberto Soriano opened the scoring in the 59th minute, courtesy of a shot that took a deflection off Stefan de Vrij.
However, Lukaku pulled the Nerazzurri level with 15 minutes remaining, pouncing to convert a rebound from a tight angle. And the striker held his nerve from the penalty spot to secure three points after strike partner Lautaro Martinez had been clumsily fouled by Riccardo Orsolini.
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Bologna's players and coaching staff were left furious by the decision to award Inter a spot-kick, soon after former Inter forward Rodrigo Palacio had seen an appeal of his own turned down at the other end, but Inter will not care after it claimed the ninth win from 11 league games to reclaim top spot ahead of Juventus' clash with Torino.
Lukasz Skorupski made excellent saves to deny Martinez and Lukaku in the first half, but Bologna's goalkeeper was fortunate to get away with a needless error in between those stops.
A dreadful pass from Skorupski gifted possession to the lively Martinez, who duly cut the ball back for Lukaku, only for Mattia Bani to slide across and block a goalbound effort.
Martinez and Lukaku both had the ball in the net before the interval, only for their respective efforts to be correctly chalked off for offside and the ball going out of play in the build-up.
Bologna had barely threatened but it claimed a shock lead after the interval when a slick passing move culminated in Soriano's 25-yarder deflecting off De Vrij to beat Samir Handanovic's despairing dive to his left.
Lukaku came close to converting a dangerous low cross from Valentino Lazaro within two minutes of Soriano's goal and eventually equalised by converting a rebound from a narrow angle, after Skorupski had saved superbly from Milan Skriniar.
Palacio's late appeals for a penalty were then rejected, before Martinez won a clear spot-kick at the other end and Lukaku sent Skorupski the wrong way from 12 yards.
Following Tuesday's narrow win over Brescia, Conte bemoaned his side's busy schedule and Inter certainly looked low on energy for much of the second half. Having been the much stronger side prior to the break, the visitors allowed their level to drop, but ultimately dug deep to claim a valuable victory.
Martinez shines as Lukaku grabs headlines
Lukaku may have scored two goals, but Martinez was the more impressive of Inter's forwards. A typically high-energy performance eventually yielded reward when he was felled by Orsolini for the match-winning penalty.
Gagliardini offers little
As Inter faded in the second half, Roberto Gagliardini struggled in central midfield, his most notable contributions a pair of needless fouls. Almost immediately after he was replaced by Matias Vecino, the visitors pulled level.
What's next?
Inter's hectic run of fixtures continues with a Champions League trip to Borussia Dortmund on Tuesday and a home game against Hellas Verona next weekend. Bologna visit Sassuolo on Friday.
