Messi at the double to help Barca top group
Lionel Messi struck twice against Celtic as Barcelona qualified for the last 16 of the Champions League, finishing top of their group.
Defeat for Celtic means that they are out of Europe, with Europa League qualification now not a possibility.
However, the Bhoys produced a much-improved display on their last outing against Barcelona, playing with aggression and intensity.
Depite an improved performance, the Scottish giants had no answer to their Catalan counterparts, who produced a solid performance of their own.
Barcelona took the lead in the 24th minute when Lionel Messi latched onto Neymar's chipped pass, hitting his half-volley first time past Craig Gordon.
Celtic came close to equalising through the in-demand Moussa Dembele, but the striker could only muster up a weak header from James Forrest's cross.
Celtic 'keeper Craig Gordon produced a contender for save of the season, denying Luis Suarez headed effort.
Barcelona then got their second 10 minutes after the break when the away side received a penalty as Emilio Izaguirre brought down Luis Suarez in the penalty area and Messi converted from the spot.