Celtic went down to a 2-0 defeat against Inter Milan in the Dublin Super Cup, despite the Italians having to play the entire second half with 10 men in an ill-tempered friendly.
The Nerazzurri made a perfect start as they broke the deadlock after seven minutes thank to youngster Luc Castaignos.
The 18-year-old Dutchman, who was signed from Feyenoord during the summer, showed his cool to slot the ball inside the near post past Lukasz Zaluska after some superb work by Goran Pandev to set him up.
Inter keeper Luca Castellazzi was in top form to deny Georgios Samaras' close-range effort, before denying the Greek striker later on in the half and then making an excellent block from Charlie Mulgrew's goalbound strike.
Just before the break, the Serie A giants were down to 10 men as referee Damien Hancock was given no option but to give Thiago Motta his marching orders.
The experienced Brazilian had already been booked for a late challenge on Emilio Izaguirre before taking out his frustration on Scott Brown.
And, just as both teams seemed happy to await the half-time whistle, Neil Lennon's men were caught cold.
Cristian Chivu's long ball was met by Giampaolo Pazzini ahead of the hesitant Zaluska to double their lead.
Inter substitute McDonald Mariga saw a shot blocked as Celtic's defence again looked vulnerable, although they were unlucky not to pull one back 15 minutes from time when substitutes Gary Hooper and Anthony Stokes combined.
Hooper played Stokes through on goal but Castellazzi was equal to his low effort and Celtic failed to get on the scoresheet.