The Spain international thinks the former Santos man could make the difference at the Vicente Calderon and says Diego Costa's potential absence would be a blow for the Rojiblancos
The Brazil international netted the equaliser in last week's 1-1 draw at Camp Nou and Xavi has little doubt he will be equally important in Wednesday's return at the Vicente Calderon.
"Neymar feels important and makes a difference for us," the Spain international was quoted as saying by AS.
"He scored the equaliser in the first leg against Atletico and he will be important again in the return on Wednesday."
The midfielder then went on to single out Diego Costa as the man to watch for Atletico ahead of this week's second leg.
The Brazil-born striker is doubtful for the match at the Vicente Calderon after picking up a hamstring problem last week and Xavi feels his absence would be a big blow for Atleti.
"Diego Costa's vital for them," the World Cup winner stated. "He provokes fouls, makes centre-backs work hard, is quick and runs all game.
"He is key for them and his absence would be important."
Costa has netted 33 goals in 44 appearances in all competitions for the Rojiblancos this season.