Gasperini's substitutions had an immediate impact as Atalanta won at lowly Cagliari 1-0 on Saturday for a club record 10th straight league victory. That ensured Atalanta will end the weekend on top of the table.
Atalanta remained two points above second-placed Napoli, who fought back to beat Udinese 3-1.
Ninth-placed Juventus remained the only unbeaten team in Serie A, but only just, when a stoppage-time penalty saw them snatch a 2-2 draw at home against bottom club Venezia.
Atalanta struggled to break down Cagliari in the first half and had Marco Carnesecchi to thank for them not being behind at the interval. The visiting goalkeeper pulled off impressive stops, including a fantastic triple save before the break.
Gasperini was clearly not happy with his team and made three changes at halftime and Atalanta immediately improved.
The coach made another two substitutions in the 64th minute, sending on the fresh legs of Nicolò Zaniolo and Lazar Samardzic for Mario Pasalic and Charles De Ketelaere.
The duo helped to break the deadlock two minutes later. Samardzic found Raoul Bellanova on the right side of the area and he knocked it back for Zaniolo to slot into the near bottom corner from close range.
Unhappy after the first half, Atalanta coach Gian Piero Gasperini's substitutions paid off. (AP PHOTO)
Gasperini, who has been in charge of Atalanta for eight years, was the coach of the year in 2019 and 2020. Last week, he picked up the monthly award for November.
Atalanta won the Europa League last season but have never won Serie A. They achieved their highest finish of third place three times under Gasperini.
Cagliari gave an impressive performance but remained just two points above the relegation zone.
Juventus were held to a fourth straight draw in Serie A but the Bianconeri will be relieved as they needed a Dusan Vlahovic penalty in the fifth minute of stoppage time to avoid losing their unbeaten record.
Just three days after an impressive win over Manchester City in the Champions League, Juventus appeared set to suffer a shock defeat to Venezia until visiting defender Antonio Candela was somewhat harshly penalised for handball.
Jay Idzes headed Venezia in front seven minutes from time after Mikael Egill Ellertsson cancelled out Federico Gatti's opener for Juventus.
It would have been Venezia's first Serie A victory over Juventus in more than 60 years.
Napoli recovered from a dismal week in which they lost the Serie A lead and went out of the Italian Cup after two straight losses - both to Lazio.
Napoli also went behind in the 22nd minute on Saturday when Udinese were awarded a penalty for a Stanislav Lobotka handball.
Alex Meret parried Florian Thauvin's spot kick but he pushed it back only to the Udinese captain, who fired the rebound into the opposite corner.
Romelu Lukaku levelled five minutes after the break after running onto Scott McTominay's throughball and holding off Lautaro Giannetti.
The Udinese defender was even more unfortunate in the 76th when he attempted to clear David Neres' shot but succeeded only in turning it into his own net. Frank Anguissa sealed the win five minutes later.
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