Felipe Anderson's brace has given Lazio a 2-0 half-time lead over Inter Milan at the San Siro.
Lazio were ahead in just the second minute when Anderson took advantage of Inter's inability to clear the danger by firing past a helpless Samir Handanovic.
Anderson could have doubled the lead just a few minutes later, but he could only volley over the crossbar after latching on to a long ball into the box.
Inter's defensive struggles were clear to the frustrated home fans, while the likes of Rodrigo Palacio and Mauro Icardi were kept quiet by Lazio's stubborn back four at the other end.
Another extended spell of Lazio pressure was rewarded eight minutes before the break when Anderson cut inside from the left before evading a couple of challenges and picking out the bottom corner.
Roberto Mancini's side were unable to produce a response to Lazio's confident performance as the visitors eased to a comfortable lead at the break.