It seems, it will be difficult for Barcelona in this match, playing away and in the 22nd minute Barcelona defender Cubarsi got a red card. But even so, it seems Benfica also still has enough difficulty to score their first goal in the first half after Barcelona played with only 10 players. But yes, in the second half it will be very possible for Benfica to score a goal and beat Barcelona in this first leg. But, if Benfica fails to beat Barcelona and the match ends in a draw, then the result will still ensure Barcelona still has a good chance in the second leg to qualify for the quarter-finals. But so far until the 43th minute, Barcelona is still leading for ball possession, and that is a good effort to not give Benfica a chance to score a goal.
A red card does not really affect a strong team but it does for those teams are not strong enough to defend their side. When a red card is given to a player, the remaining players have to re-strategize in the field to defend themselves and strike more to scare the opponent and with that fear, the side with 10 players can score again. Barca has not to worry because of a red card to a player instead focus and strike more. Barcelona now is leading with 1 - 0. Raphinha scored the goal at the 61 minutes in the second half, though Benfica tackling Barcelona but Barca is also resisting their attacks. From my own view, Barcelona will win the match.