Barcelona are in great spirits to achieve another good result on Saturday. They go into the match very confident, and if they stay professional they can come out on top, but with such a big lead in La Liga even a loss won't be a drama for them. Real Madrid will be under real pressure and Barca can play in a relaxed way waiting for the right moment to strike their blow.
In my opinion, they could do something similar to Wednesday's match, waiting for their rival to go forward and then counterattack with efficiency to score goals in the second half.

Source: betting.betfair.com

After a run of just one win in five games, Barcelona got a much needed confidence boost in beating a good Sevilla side 4-2, with Lionel Messi working his magic, scoring a sensational hat-trick and providing the assist for Luís Suárez to score a much needed goal.
Real Madrid are in good form themselves, winning every game since the first leg, so I expect a cautious approach from both sides, and not many goals in the contest. I can see it going 2-1 either way.
Messi continues to post ridiculous numbers at Barcelona and is their main man, so when he is on top form - like at Sevilla - then you'd make Barca favourites to qualify. But if he doesn't show up or Madrid manage to contain him, things will get tougher for the visitors.

Source: betting.betfair.com