The Catalan giants beat arch-rivals Real Madrid 4-3 at the Bernabeu on Sunday to breathe new life into their title defence.
The thrilling triumph - which was inspired by a hat-trick from Argentine superstar Lionel Messi - means Gerardo Martino's side are now within one point of leaders Atletico Madrid and Real.
With nine league matches remaining, a thrilling finish to the season is anticipated - and Barca can now expect to play a major part in the race for the crown.
Defeat to Real would have seen them fall seven points behind Carlo Ancelotti's team, but midfielders Sergio Busquets and Xavi now feel retaining their Liga crown is a realistic aim.
"They (Real) are a direct rival and if we had lost we would have been very far from the top of the table," Busquets said after Sunday's win.
"To win La Liga we have to win all the games we have left. We're strong at home and we need to be more consistent on the road."
Xavi added: "We're very content and happy. Our morale is very high. We're one point away from Real Madrid and Atletico Madrid - it will be a great fight for the title."
With Spanish league positions being decided on a head-to-head record, and not goal difference, if teams are tied on points, the impact of Barca's victory in the capital may be felt at the season's end.
The Catalans' win gives them the edge over Real in their head-to-heads - following their 2-1 success in the reverse fixture in October - while the club's second clash with Atletico on the final day of the season could prove crucial.
Barca and Atletico will also meet in the UEFA Champions League quarter-finals next month.
Barca captain Carles Puyol (knee) remains in doubt for the home game with Celta, while Jonathan dos Santos (knee) and Isaac Cuenca (hamstring) will definitely miss out.
Messi's treble in Madrid - his second hat-trick in a week after he also hit three in the 7-0 demolition of Osasuna seven days earlier - has taken him to 21 league goals for the season, and he and fellow forward Alexis Sanchez have combined for 38 goals - five more than the entire Celta squad.
Celta, coached by Barca legend Luis Enrique, sit 12th in the league but just six points clear of the relegation zone.
They did win their last away fixture - a 1-0 success at Levante - but that is their only triumph in their last five matches.
Just one goal in their last four home matches has seen them lose the momentum gained in January and early February, but Enrique will hope his players lift themselves for the visit to Camp Nou.
Celta will welcome back defenders Gustavo Cabral and Jon Aurtenetxe from suspension.
The meeting between the two sides earlier this season ended in a 3-0 win to Barca, though, and a similar result would not surprise with Martino's men riding the crest of a wave following their Clasico success.
