Xavi welcomed the returns of Pedri and Frenkie de Jong as the Barcelona midfielders were passed fit to feature in Sunday's clash with Atletico Madrid.
Pedri has not played for Barca since he sustained a hamstring injury during February's 2-2 Europa League draw against Manchester United.
The Spain international initially looked set to return for last month's LaLiga meeting with Clasico rivals Real Madrid – a game Barca won 2-1 – only to suffer a setback in his recovery.
While Pedri has missed a total of 11 games, Barca have also been without fellow midfielder De Jong for their last four matches after he sustained a similar injury.
Barca have struggled for creativity in back-to-back goalless draws against Girona and Getafe in LaLiga, but they will have both midfielders available when they host in-form Atleti.
"Pedri helps us, also Frenkie," Xavi said. "They are essential, vital players, however you want to say it, but we have played great games without them.
"In the end, it is about the idea and the game model. We are in a privileged situation in LaLiga and the players have understood this well. We have played great games without some crucial players.
"Pedri is key in the last pass. He associates very well with Robert [Lewandowski], they get along very well. It's very good news to get him back, not only for Robert."
Having built an 11-point lead over second-placed Madrid with just nine games remaining, Xavi knows a first league title since 2019 is now Barca's to lose.
However, with Diego Simeone's visitors winning six successive league games ahead of their trip to Camp Nou, the Blaugrana boss expects a difficult challenge next time out.
"We have an important advantage and we have to make it good," Xavi said. "Losing the League would be anything but the fault of the other teams, it would be our fault.
"Every game is a final from now on. If we beat Atletico, we would eliminate them as a rival. We are in a privileged situation but we cannot relax.
"Tomorrow will be a difficult game, Atleti are the best team in the league at the moment, they are the fittest team in LaLiga right now."