Udinese slipped to their first defeat of the season at Bluenergy Stadium on Monday as Lazio came from behind to claim three points and continue their 100% start.
After a goalless opening 45 minutes, Jesper Karlstrom gave us the lead when he ran onto Keinan Davis's clever pass and finished past Mandas.
The visitors found an equaliser 15 minutes from time when Zaccagni's cross was steered in by Davide Frattesi and completed the turnaround two minutes before stoppage time thanks to Gudmundsson's header.
The result leaves Udinese on four points as their attentions now turn to next Monday's trip to Inter at San Siro.
Udinese 1-2 Lazio (0-0)
Scorers: Karlstrom 49, Frattesi 75, Gudmundsson 88.
Udinese (3-4-2-1): Okoye; Abankwah (Bertola 76), Solet (Kabasele 38), Ebosse; Vojvoda, Karlstrom (cap.), Piotrowski (Miller 15), Kamara; Gomez (Bayo 46), Ekkelenkamp; Davis (Zarraga 76).
Subs not used: Mrozek, Padelli, Lovric, Gueye, Chakvetadze, Vinciati, Jovanovic.
Coach: Runjaic.
Lazio (4-3-3): Mandas; Floriani, Doekhi, Provstgaard, Tavares; Frattesi (Gudmundsson 79), Belahyane, Taylor; Isaksen (Cancellieri 53), Pinamonti (Noslin 53), Zaccagni (cap.) (Pedraza 90+1).
Subs not used: Motta, Renzetti, Przyborek, Lazzari, Bordon, Sutalo, Serra, Farcomeni.
Coach: Gattuso.
Referee: Tremolada.
Assistants: Rossi L., Monaco.
Fourth official: Maresca.
VAR: Maggioni.
AVAR: Rutella.
Booked: Piotrowski 12, Miller 22, Isaksen 25, Karlstrom 45+3, Bayo 67, Bertola 85.
Added time: 4+5 minutes.
Attendance 23,312 (€320,275).