Watch as Inter ran riot, including a stunning Alexis Sanchez volley and Hakan Calhanoglu scorcher, but Cagliari goalkeeper Alessio Cragno was Man of the Match as he faced 15 shots on target.
It was one-way traffic at San Siro, with Lautaro Martinez nodding in a Calhanoglu corner, then seeing his penalty saved by Cragno.
Serie A | Inter 4-0 Cagliari: Nerazzurri new leaders in style
The Sanchez volley was set up by an inspired Nicolò Barella cross over his shoulder from the by-line, while Calhanoglu hit a trademark rocket into the top corner.
Lautaro Martinez made the most of another Barella assist, but Cragno performed heroics to keep the scoreline down on Barella and Milan Skriniar.