Fiorentina breathed life into the Serie A title race by producing a commanding performance to beat bitter rivals and pacesetters Juventus 2-1 on Sunday.
Roma's 1-0 win over Udinese earlier in the day cut Juve's lead to a single point and they rarely looked like providing a response, as Paulo Sousa's men dominated for much of the match and deservedly secured a rare victory over their fierce foes.
Juve were guilty of a particularly limp showing in the first half, as Fiorentina took control with an intense display and carved open numerous chances.
Nikola Kalinic eventually gave the home side the lead with his ninth league goal of the season, late on in an opening period that offered Juve few reasons to be positive.
Fiorentina deservedly doubled their advantage in the 54th minute through Milan Badelj's fluke effort, but Gonzalo Higuain swiftly pulled one back with his sixth Serie A goal in four outings.
Juve, who still have a game in hand on their title rivals, piled the pressure on towards the end as things got desperate, but Fiorentina were ultimately good value for the triumph.
Leonardo Bonucci's pre-match snipe suggesting this was Fiorentina's "game of the year", but only a "stepping stone" on Juve's path to glory seemed to be given credence by the hosts' start, as they attacked with brilliant ferocity.
Matias Vecino was particularly threatening, forcing Gianluigi Buffon into a strong save seven minutes in after latching on to a loose ball on the edge of the area.
The Uruguayan went even closer a few minutes later, darting into the left side of the area to offer support to Kalinic and eventually slamming a left-footed effort on to the post.
Fiorentina finally made the most of their superiority eight minutes before the break - Kalinic beating Buffon from a tight angle after being fed into the box by Filippo Bernardeschi.
Juve almost levelled on the stroke of half-time, but Maxi Olivera crucially blocked Higuain's goal-bound effort to preserve the hosts' lead.
Fiorentina remained in the ascendancy early in the second period and should have scored a second four minutes after the restart, but Kalinic delayed his finish after racing on to Bernardeschi's incisive pass and Buffon made an important block.
Buffon was beaten a few moments later, though, as Badelj's half-volleyed pass from deep sailed all the way through without a touch from anyone else and found the bottom-right corner.
Juve gave themselves a lifeline just before the hour mark. Higuain stabbed home from close range after Sami Khedira's cross struck Stefano Sturaro and dropped kindly for the Argentinian.
Fiorentina generally did a good job of keeping Juve at arm's length thereafter, but had two lucky escapes in the final 10 minutes.
Ciprian Tatarusanu closed his legs just in time to keep a Higuain header out and, in the ensuing scramble, Giorgio Chiellini saw his effort kept out by the goalkeeper.
Paulo Dybala then blazed over after darting into the box with two minutes to go, letting Fiorentina off the hook.