Adam Szalai scored a hat-trick as Mainz blasted past Hoffenheim to make a push up the Bundesliga table.
Szalai was on target in the 21st, 46th and 64th minutes to increase his season's goal tally to seven.
Mainz jumped to 14 points with the victory while Hoffenheim - who have the worst defensive record in the league with 20 goals conceded - remained on just eight points.
Hoffenheim were close to taking the lead after 12 minutes but Joselu could only fire into the side-netting from a tight angle.
Mainz forged ahead nine minutes later with Junior Diaz crossing from the left to Szalai, who outjumped Marvin Compper and headed home.
The visitors nearly equalised in the 37th minute following a counter-attack, but Joselu redirected Roberto Firmino's cross just wide of the far left post.
Mainz doubled their lead just 19 seconds after the restart as defender Jannik Vestergaard could not control a ball and Elkin Soto played forward to Szalai, who beat Hoffenheim goalkeeper Tim Wiese.
Hoffenheim had a chance to cut the deficit to 2-1 but Mainz goalkeeper Christian Wetklo fended away Takashi Usami's shot in the 61st minute.
Szalai completed his hat-trick in the 64th minute by heading home Nicolai Muller's corner, the first competitive treble of his senior career.
Hoffenheim had one final chance in the 88th minute but Wetklo saved a header by Swiss substitute Eren Derdiyok to secure the clean sheet.