Luciano Spalletti could take a little comfort from the fact his Inter Milan side's second-half collapse was "something of a novelty" after Udinese ended their unbeaten start to the Serie A season.
The Nerazzurri were top after avoiding defeat in their opening 16 games but in-form Udinese came to San Siro and halted their run with goals from Kevin Lasagna, Rodrigo De Paul and Antonin Barak.
Mauro Icardi had reached 17 goals for the league campaign with his quickfire response to Lasagna's first-half opener but Inter boss Spalletti was left to rue a disappointing 3-1 loss.
He told Inter's website: "I'm not happy, just as I wouldn't be after any other defeat. But we're now not used to losing, so that obviously makes this one hurt a bit more.
"We need to work out why, in the second half, we were scared to go after the ball, making mistakes and poor choices all the time.
"In the first half we did the right things and played well, so what happened after the break was unexpected.
"We're used to doing better, so what we saw in the second half was something of a novelty."
Udinese, who have now won four straight games in all competitions, cheekily dedicated their triumph in Milan to third-division club Pordenone.
The Friulian minnows, who are based in a town not that far from Udine, took Inter all the way to a penalty shootout in the Coppa Italia in midweek, with the Nerazzurri just about squeezing through.
A tweet from Udinese post-match on Saturday read: "Hey, Pordenone Calcio, mission accomplished!"
After seeing his team climb to 11th in the table, Bianconeri boss Massimo Oddo told La Gazzetta dello Sport: "We are making great strides, but there is no magic wand.
"We still have to improve a lot and in the first half here, we suffered a lot."