Lazio suffered its worst defeat ever at home when defending champion Inter Milan achieved a crushing 6-0 victory in Rome.
Lazio started the night level with Inter and top of the Europa League table, but had no answer to a stunning attacking display from Simone Inzaghi's side.
They are unbeaten in 12 home matches and have not lost in front of their own fans since March.
Hakan Calhanoglu put Inter in front with a penalty kick in the 41st minute, after a penalty kick was awarded for handball, and Federico Dimarco doubled the score before the end of the first half with a direct shot.
Nicolo Barella scored the third goal six minutes into the second half, before Denzel Dumfries scored two minutes later and Carlos Augusto and Marcus Thuram completed the hat-trick late on.
Inter remains in third place in the standings with 34 points from 15 matches, and is three points behind leaders Atalanta and has a game in hand.
Lazio's previous record defeat at home was a 5-0 loss to Fiorentina in 1959.
Their three biggest Serie A defeats were all to Internazionale: this one came after 8-1 (in 1934) and 7-0 (in 1961) defeats in Milan.
