England keeper Joe Hart made a mistake to concede an equalising goal and was then beaten by a penalty as his Torino debut ended in defeat at Atalanta.
Hart, on loan to the Italian club from Manchester City, failed to deal with a corner as he palmed the ball to Andrea Masiello to slot home for the hosts.
The 29-year-old was then beaten by Franck Kessie’s late spot-kick as Atalanta fought back to win 2-1.
It was their first Serie A victory of the season and Torino’s second loss.
Things picked up when his team went in front through a well-struck Iago Falque free-kick eight minutes into the second half.
Up to that point, it had been a virtual watching brief for Hart, bar one smart low block in the first half.
But things went downhill just two minutes later when he tried to intercept a corner but failed to reach the ball properly and was left stranded as Masiello made it 1-1.
Hart had a chance to make amends when Atalanta were awarded a late penalty, but Kessie sent him the wrong way from the spot to earn the hosts their first points of the season.
Bad weekend for City keepers
Hart’s City career was ended – for now at least – by Guardiola replacing him for the opening three Premier League games with Willy Caballero before signing of Claudio Bravo from Barcelona.
Chile international Bravo made his City debut in Saturday’s 2-1 derby win over Manchester United at Old Trafford – but the 33-year-old produced a far from convincing performance.
However, Hart was unable to give critics of Guardiola’s decision to let him leave further ammunition at the start of his season-long stay in Italy.