Domenico Berardi scored a first-half hat-trick as Sassuolo edged Fiorentina on Tuesday to boost their Serie A survival hopes.
With the Italian forward in top form, Sassuolo ran out 4-3 winners in Florence.
Berardi opened the scoring from the penalty spot in the 22nd minute and he added his second 11 minutes later.
The 19-year-old completed his hat-trick three minutes before the interval.
Gonzalo Rodriguez scored Fiorentina's first from the penalty spot in the 57th minute before Nicola Sansone extended Sassuolo's lead back to three goals shortly after.
Strikes from substitute Giuseppe Rossi and Juan Guillermo Cuadrado pulled Fiorentina back to 4-3 just 15 minutes from the end but the hosts could not find the equaliser.
The victory has lifted Sassuolo out of the relegation zone and into 16th place, two points clear of danger with two games remaining.
Fiorentina are fourth in the standings, four points above Inter Milan.
The hosts went into the contest looking to bounce back from Saturday's 3-1 defeat to Napoli in the Coppa Italia final.
Sassuolo's Marcello Gazzola was first to test Antonio Rosati with a hard drive from 30 yards which the Fiorentina goalkeeper saved.
The visitors were handed a great opportunity to go in front when the referee pointed to the spot following Borja Valero's hand ball in the box.
Berardi struck the spot-kick towards the left corner of the goal and out of Rosati's reach.
Fiorentina almost pulled level in the 27th minute but Alessandro Matri's close-range header from Valero's cross went over the bar.
Sassuolo then doubled their advantage when Sansone set up Berardi in the box and he drilled a left-footed effort past Rosati.
The visitors continued to press forward and made it 3-0 before half-time when Berardi poked home his 16th goal of the campaign after good work from Simone Zaza.
Fiorentina were handed a lifeline before the hour mark when they were awarded a penalty after Alessandro Longhi brought down Joaquin in the area.
Rodriguez made no mistake and beat Sassuolo goalkeeper Gianluca Pegolo with a rigth-footed effort towards the far post.
Sassuolo made it 4-1 in the 64th minute when Berardi spotted Sansone in the six-yard box and his strike found the back of the net.
In the 72nd minute, Rossi got behind Valero's cross and struck the ball past Pegolo to score his first goal since returning from a four-month injury lay-off.
Fiorentina found the net again three minutes later when David Pizarro served Cuadrado in the box and he scored with a right-footed effort from the heart of the area.
Fiorentina, who could have cemented a fourth-place finish with a win, ran out of steam as Sassuolo held on for a vital victory.