Giorgio Chiellini's first-half goal was cancelled out by Aleksandar Trajkovski as Italy struggled to a 1-1 draw against Macedonia in Turin on Friday, condemning the four-time champions to the World Cup play-offs.
Gian Piero Ventura's side were jeered off the pitch at the Stadio Olympico after failing to secure the three points demanded against the modest Macedonians as Spain qualified as Group G winners after beating Albania 3-0.
Chiellini tapped in just before half-time to boost home hopes but Palermo striker Trajkovski came on as a second-half substitute to equalise on 77 minutes, leaving Italy second behind Spain with one qualifying game left in Albania.
"We had perhaps fooled ourselves that we were more advanced in our work than we really were," said veteran defender Chiellini.
"Once we had broken the deadlock, we should have controlled it a bit better, as Macedonia weren't really dangerous for 75 minutes.
"We understand why the fans are upset."
The result not only means Italy are guaranteed second place behind Spain but the result could have a disastrous impact on their ranking in the draw for November's play-offs.
"I think the whistles were deserved, even if I think in principle you should never jeer the national side," said Ventura.
Ventura gave Bologna's Simone Verdi and Roberto Gagliardini of Inter Milan their first senior starts as Italy struggled with injuries.
And the Italians toiled while attempting to break down the dogged Macedonians before Chiellini -- earning his 93rd cap for Italy -- found his way through five minutes before the break.
The breakthrough came following a corner, as Lorenzo Insigne's through ball found Ciro Immobile and he rolled on for Chiellini.
It was almost 1-1 moments later, after a slack Leonardo Bonucci pass gave away possession on the edge of the box, but Chiellini forced a corner.
Macedonia poured forward in the second half with striker Trajkovski picking up a cross from skipper Goran Pandev to blast past Buffon, the veteran goalkeeper decked out in the new Azzurri blue kit with the restyled logo for the 2018 World Cup finals in Russia.
"Italy are a great side, they will get to Russia, but you could tell they had nothing to play for, as they knew they'd be second," said Genoa striker Pandev.
But the Azzurri, still in a fragile state mentally and physically after a crushing defeat to Spain last month, are not yet guaranteed a place in the play-offs, nor of being top seeds in the draw.
Italy are second in Group G behind Spain with their final qualifying game in Albania, who are third, on Monday.
In the group, Israel are fourth ahead of Macedonia and Liechtenstein.
Despite bringing in new blood to an ageing team since taking over a year ago, Ventura's side has been badly hampered by injury.
Five first-choice players are absent in midfield -- Daniele De Rossi, Marco Verratti, Lorenzo Pellegrini, Claudio Marchisio and Riccardo Montolivo.
Top striker Andrea Belotti has been ruled out for a month and is also uncertain for the play-offs on November 9 and 14.
"Officially we're second," said Ventura. "If we go to the play-offs I hope that five or six players will have returned.
"We have to now try to get everyone back and try to focus seriously on the goal."