Joe Hart endured a nightmare Torino debut as his error set Atalanta on their way to a 2-1 victory at Stadio Atleti Azzurri d'Italia.
The Manchester City loanee became the first English goalkeeper to appear in Serie A when he replaced former Liverpool man Daniele Padelli in the visitors' line-up, but his bow ended in disappointment as he dropped a set-piece to allow the hosts to equalise.
Hart joined the Italian club last month after new City boss Pep Guardiola opted to sign Claudio Bravo and, although the Chilean was then culpable for a goal in Saturday's Manchester derby, his mistake was echoed here by his predecessor at the Etihad Stadium.
The England international did, however, record a passing success rate of over 80% - topping Bravo's 70.5% effort - having been criticised for his distribution in Manchester.
Hart was called into action for the first time in the 20th minute, parrying well from Franck Kessie's angled strike before an Atalanta forward inadvertently blocked the rebound.
A routine stop followed as Torino were increasingly put under pressure, and, while he was redundant as the hosts squandered a number of fine chances at close range, a couple of instances of miscommunication led to nervy moments.
Iago Falque punished Atalanta's profligacy in stunning style, curling a free-kick beautifully beyond the stranded Marco Sportiello.
However, the response was instant. If the home goalkeeper had little chance with the opener, Hart's error was obvious as he spilled a corner at the feet of Andrea Masiello, who ruthlessly converted.
The 29-year-old was handed an opportunity to redeem himself with eight minutes remaining when Atalanta won a penalty, but Kessie sent him the wrong way from the spot.