The 31-year-old has spoken about his disappointment over the result against the Italian club and claims the team plan to bounce back against Osasuna
The Catalan club looked set to win their opening group stage game after Pedro and David Villa scored to overturn Alexandre Pato's early goal.
However, Thiago Silva's header in the 92nd minute rescued a point for the Serie A champions, something Xavi believes was undeserved.
"What happened on Tuesday is pure bad luck, totally unfair," the 31-year-old told Barcelona TV.
"The other day [the 2-2 draw versus Sociedad] we dropped our intensity in the second half of the game, but this time the team played well, we pressurised them until the 90th minute and we had possession of the ball."
The Spain international claims the reigning Liga and Champions League winners will now focus their attention on the upcoming clash against Osasuna.
"We have to win now on Saturday. We'll battle on, we know we have a great team to carry on winning things and we're competitive.
"It makes us very excited and every year we start from scratch without looking back."
Xavi has made six appearances for Barca in all competitions so far this season, completing 430 minutes on the pitch.