Skipper Scott Brown was sent off as Celtic slumped to a 1-0 defeat by Barcelona in their Champions League clash at Parkhead.
The home side were reduced to 10 men in the 58th minute when Brown was red carded by referee Stephane Lannoy after a kick at Neymar following his original foul on the Brazilian.
The Hoops came close to opening the scoring moments later when substitute James Forrest, on for Mikael Lustig, had a powerful volley saved by Victor Valdes before Charlie Mulgrew came within inches with a header.
However, the Scottish champions were dealt another blow in the 76th minute when Cesc Fabregas headed Barcelona into the lead.
Celtic keeper Fraser Forster denied Neymar twice and also substitute Alexis Sanchez, who had set up the goal, in the closing stages as gaps opened up in the Parkhead defence.
But it was a spirited performance by Neil Lennon's side, who as expected chased the ball for most of the game, especially in the first half.
Despite that Forster had little to do and the home side were given a round of applause by their fans at the end of the game.
However, Brown's dismissal made an uphill task even more difficult.
Celtic play Ajax in their next group fixture on October 22 and after losing 2-0 to AC Milan in their Group H opener, they will have to fight for Champions League survival without the Scotland midfielder who let his side down.
The 'Tifosi' display inside Celtic Park before the game, where coloured cards were held up by fans all around the packed stadium, set the mood for another night of European excitement in the east end of Glasgow.