The Italy Under-21 striker struck three times at the Stadio Benito Stirpe, punishing Sassuolo's defensive mistakes and helping Frosinone recover from an open first half in which both teams found the net twice.
The victory moved Frosinone into fourth place with 13 points from seven matches, while Sassuolo remained 11th on eight points.
Calò opens the scoring as both teams trade goals
Frosinone made the perfect start when Giacomo Calò opened the scoring in the ninth minute. Sassuolo were caught attempting to play out from the back, allowing Calò to capitalise on a mistake and finish past goalkeeper Arijanet Muric.
Sassuolo responded through Domenico Berardi in the 15th minute. Darryl Bakola recovered possession and launched a pass forward, allowing Berardi to race through, round goalkeeper Lorenzo Palmisani and score into an unguarded net.
Frosinone regained the lead in the 26th minute when Raimondo took advantage of Muric's failure to deal with a cross, poking the ball home from close range.
The striker doubled his tally four minutes later after another defensive error. A poor backward header from Cas Odenthal caused problems for Muric, and Raimondo reacted quickly to steal the ball and finish.
Sassuolo refused to give up. Kristian Thorstvedt reduced the deficit to 3-2 in the 37th minute after combining with Sebastiano Esposito, who helped create the opening for the midfielder to finish past Palmisani.
Raimondo completes his hat-trick
The match continued at a high tempo after the break, with Sassuolo looking for an equaliser and Frosinone seeking to restore their two-goal advantage.
Raimondo delivered the decisive moment in the 57th minute. Giorgi Kvernadze supplied the cross during a second phase of play following a corner, while Fares Ghedjemis forced Muric into a save with a header across goal.
The rebound fell into Raimondo's path, and the forward finished to complete his hat-trick and put Frosinone 4-2 ahead.
Sassuolo were unable to mount another comeback, as Frosinone held on to claim an important victory in front of their home supporters.
Frosinone strengthen their top-four push
The result represented a strong response from Frosinone after their previous 3-0 defeat against Napoli. Their early-season form had already included victories over Fiorentina, Venezia and Como, and the win over Sassuolo added another significant result to their campaign.
Raimondo's three-goal performance was the standout feature of the night, while Sassuolo will be concerned by the defensive errors that allowed the hosts to score repeatedly.
Frosinone now sit fourth with 13 points, while Sassuolo have eight points in 11th place.
Match details
• Frosinone: Giacomo Calò 9', Antonio Raimondo 26', 30', 57'
• Sassuolo: Domenico Berardi 15', Kristian Thorstvedt 37'
Final score: Frosinone 4-2 Sassuolo
Competition: Italian Serie A, Matchday 7
Date: Friday, 16 October 2026
Venue: Stadio Benito Stirpe, Frosinone, Italy
Antonio Raimondo's hat-trick proved decisive in a six-goal contest, giving Frosinone a valuable three points and leaving Sassuolo to reflect on costly mistakes at the back.