- Ciro Immobile (12' Pen)
- Roberto Gagliardini (36')
Last season's runners-up have four points from their first five league matches and are down in 15th place.
Lazio have equalled their poorest start at this stage of the season since the three points for a win era began in 1994, matching that of the 2001-02 campaign.
"We ought to do more, but we're struggling at the moment," manager Maurizio Sarri told Sky Sport Italia, urging patience.
"Clearly, many things aren't working well at the moment but, as we said before the match, it is difficult to think we can just emerge from this negative moment quickly."
But an unmarked Gagliardini equalised for the visitors nine minutes before the break by tapping in a cross from close range.
Immobile came close to scoring again near the hour mark but his close-range volley hit the inside of the far post.
Home fans expressed their disappointment with loud boos as the players headed to the dressing rooms after the game.
"Up until their equaliser, we were passive and handed the game to our opponents, so at that stage we did deserve the jeers," said Sarri.
"I think if there's something you can complain about now it's that Lazio do not score as many goals as they ought to for the amount of possession and control."
- Rosario Abisso