Champions League debutants CFR 1907 Cluj stunned AS Roma 2-1 in a Group A clash at the Stadio Olimpico in Rome on Tuesday.
The Romanians thoroughly deserved their victory with Argentine Juan Culio scoring twice in response to Cristian Panucci's opener for the Italians.
Cluj, mostly a hodge-podge of little-known Portuguese and South American players, were resolute at the back while showing confidence, speed and potency on the counter-attack.
Roma were missing first choice centre-back pairing Philippe Mexes and Juan while captain and talisman Francesco Totti started on the bench in his comeback from injury and they were second best throughout most of the game.
The hosts started well enough, though, as a sweeping move from left to right, typical of Roma, ended with Brazilian fullback Cicinho crossing for Mirko Vucinic to stab wide on 14 minutes.
The Montenegro forward then latched onto a long punt forward from Panucci and beat goalkeeper Eduard Stancioiu to the ball but prodded his effort onto the post.
Roma's pressure told and they took the lead on 17 minutes after Daniele De Rossi dispossessed a dawdling Culio near the corner flag and crossed for Panucci who stooped to head home at the near post.
But that seemed to spur on the visitors who responded in style and exposed Roma's makeshift centre-half pairing of Panucci and Marco Cassetti.
Argentines Sebastian Dubarbier and Culio, as well as Uruguayan Alvaro Pereira all had chances on the counter before the Romanians levelled on 27 minutes.
Left winger Culio made up for his earlier mistake by shrugging off Rodrigo Taddei, playing a one two with Eugen Trica and taking the return - a back-heeled flick - in his stride before firing home low past goalkeeper Doni.
Towards the end of the half Roma fans started jeering their own team as Cluj had clearly wrested the ascendancy from the hosts.
Roma off lightly
Things could have been worse too for the Italians as Portuguese midfielder Dani forced Doni into a sprawling save six minutes from the break.
Whatever coach Luciano Spalletti told his side during the half-time interval it had no effect as Culio grabbed his second with a left-foot volley after Cassetti only partially cleared Trica's chip into the box.
That prompted Spalletti to introduce Totti into the fray instead of John Arne Riise with Vucinic switching to the left flank.
Even then Cluj went closest to scoring as Gabriel Muresan curled a freekick just past the post before Cicinho escaped with a bearhug that prevented Culio from running clean through on goal.
The visitors remained the more dangerous and Argentine substitute Sixto Peralta was unlucky to see his 71st minute header from a Tony cross crash back off the bar.
It was only in the dying moments that Roma started to exert any real pressure but it was too little too late and the jeers at the final whistle from a spartan crowd told their own story.