Alba delivered Barcelona their third goal against Elche following strikes from Lionel Messi as a tepid opening 45 minutes gave way to a much stronger second half. The win moved them into third place in LaLiga, behind Real Madrid and leaders Atletico Madrid.
"This will help our confidence a lot," Alba told reporters.
"The draw (with Cadiz) was a huge blow to the whole team and showed that if we are not at our 100% best we find it very hard to win. We struggled on Sunday and in the first half here too but we were better in the second and the goals arrived."
Barcelona will face Sevilla in consecutive matches - first in La Liga, and then in the second leg of the Copa del Rey semi-final where they trail 2-0 on aggregate. Sevilla sits just two points behind them in the La Liga table.
Their last-16 decider against PSG, meanwhile, comes on March 10.