A Luiz Suarez second-half brace helped Barcelona to stage a comeback as they recorded a 2-0 win over Inter Milan at the Nou Camp.
A game played in two halves saw the Italians dominated the first department before a spirited second half from the Catalan club won them the maximum.
Inter started the game strongly and took a deserved lead when Lautaro Martinez tucked home the opener.
Antonio Candreva thought he had doubled the lead for his outfit when he put the ball into the net only to be flagged offside.
Lautaro Martinez rose high and met Antonio Candreva cross with a powerful header but Marc-Andre ter Stegen thwarted the striker's effort as the first half ended 1-0 in favour of the Italian club.
Barcelona upped their game after the restart as coach Ernesto Valverde replaced Sergio Busquets with Arturo Vidal.
The substitution had an effect on the game, when Vidal assisted Suarez for Barca's equaliser 5 minutes after coming on.
His cross was met by the Uruguay striker who volleyed home to level the game.
Lionel Messi after being quite in the game for long spells work his magic in the 84th minute and laid the ball to Suarez who controlled it and poked home.
Elsewhere Genk held Napoli to a draw, Slavia Prague lost at home to Dortmund, Liverpool recorded a slim win over Salzburg, Chelsea beat Lille away, Zenit thrashes Benfica and RB Leipzig lost to Lyon.
Below is the full results
Genk 0-0 Napoli
Slavia Prague 0-2 Dortmund
Barcelona 2-1 Inter
Lille 1-2 Chelsea
Liverpool 4-3 Salzburg
RB Leipzig 0-2 Lyon
Valencia 0-3 Ajax
Zenit 3-1 Benfica