Lautaro Martinez gave Inter the lead on the half-hour and Sergej Milinkovic-Savic equalised for the hosts 10 minutes after the break before tempers flared.
Inter Milan dropped their first two points of the season when they were held to a 1-1 draw by Lazio on Sunday in a bad-tempered Serie A match in which one player from each side was sent off.
Lautaro Martinez gave Inter the lead on the half hour and Sergej Milinkovic-Savic equalised for the hosts 10 minutes after the break before tempers flared.
Lazio had forward Ciro Immobile, topscorer in Serie A last season, sent off after 70 minutes following a clash with Inter midfielder Arturo Vidal although it seemed harsh.
Immobile went down under a challenge from Vidal, who bent down over his opponent and Immobile appeared to prod the Chilean who reacted theatrically.
Inter, who have seven points from three games, also finished with 10 men after Stefano Sensi was dismissed following a clash with Gil Patric, who also made the most of the incident.
Lazio, fourth last season, have four points from three games.
Inter, runners-up last season, had started the campaign with a 4-3 win over Fiorentina and 5-2 thrashing of Benevento.
Antonio Conte's side went ahead with one of the first chances of the match as Ivan Perisic tried to squeeze between two defenders and the ball ran loose to Martinez, who turned it in from 12 metres.
It got worse for Lazio as they lost Stefano Radu, Adam Marusic and Bastos to injury before halftime.
Romelu Lukaku hit the bar for Inter after the break but it was Lazio who scored next as Milinkovic-Savic met Francesco Acerbi's cross with a towering header.
The match degenerated after that although Marcelo Brozovic nearly snatched a winner for Inter with a shot which was deflected onto the post.