Just a week after beating South Africa for the first time, Italy came back to earth with a thud, losing to Tonga 19-17 on the last kick of the match on Saturday.
Scrumhalf Sonatane Takulua converted the winning kick after stand-in captain Simone Favaro was penalised.
Italy scored two tries to one and had two more tries disallowed. But it started and finished the second half down a man because of yellow cards. Even so, fullback Edoardo Padovani seemed to give the home side victory with a penalty in the 78th minute.
But Takulua got a chance at his fourth penalty kick and didn't miss, and Tonga earned its first win over Italy since their first match-up, which occurred at the 1999 Rugby World Cup.
"We are very disappointed because we had a lot of opportunities during the match," Italy coach Conor O'Shea said.
"Credit to Tonga because they never went away. But our execution wasn't good enough today, nor was our discipline.
"We had two or three opportunities near their line and the game would have been over. It happens. I'm very positive for the future. It's a long and hard journey but we've started the change."
Italy beat the Springboks 20-18 just one week ago but the pressure was different this time.
Italy was the favourite against Tonga, even without captain Sergio Parisse, its most capped player who was banned by the French club leagues. Flanker Favaro took over the captaincy for the first time.
Italy reached halftime 7-3 ahead but Tonga were troubling them regularly.
Tonga No. 8 Tevita Koloamatangi was seriously injured and, after several minutes of treatment on the pitch, was taken off on a stretcher, his replacement Valentino Mapapalangi was yellow-carded three minutes after coming on for a dangerous tackle on Cittadini, but that seemed to galvanise Tonga and Takulua kicked over his first penalty.
Prop Sami Panico was sent to the sin-bin on the stroke of halftime for a high tackle on Takulua, meaning Italy had to play the first 10 minutes of the second period with 14 men.
Takulua's second penalty reduced the deficit to one, and Tonga took the lead in the 52nd minute when centre Siale Piutau evaded Padovani down the left and sprinted into the left corner for a converted try, and a 13-7 lead.
Italy reacted by changing the halves: Sending on Tommaso Allan and Edoardo Gori for Carlo Canna and Giorgio Bronzini. It worked.
Inside centre Luke McLean caught his own chip and offloaded to Allan to score before Allan added the extras, and Italy was back in front by one.
Allan went from hero to villain when he was shown a yellow card in the 72nd, and Takulua's third penalty made it 16-14.
There was still time for the lead to change two more times, with Italy taking it back with a penalty before Tonga responded in kind to take a famous win.
