Barcelona ace Lionel Messi struck twice as they won 3-1 against Champions League opponents Olympiakos.

Dimitrios Nikolaou opened the scoring, turning Gerard Deulofeu's goal into his own net, before Messi doubled Barca's lead with a free-kick -- although not before Gerard Pique had been sent off for a second booking on the stroke of half-time.

Barça's third goal arrived via Lucas Digne, who finished smartly after some brilliant foot work from the once again inspired Messi, before Nikolaou scored a late consolation.

It leaves Barca with nine points, three wins from three and top spot in Group D, with their place in the knockout rounds looking increasingly assured.