Gerardo Martino's Barca are top of the table on goal difference alone, and their opponents this weekend have displayed marginally better recent form in the league.
Atletico have taken maximum points from their last five games, keeping four clean sheets and seeing striker Diego Costa score six goals in the process.
Barca suffered their only league defeat of the season to date when losing 1-0 to Athletic Bilbao at the start of December, but have bounced back by taking nine points from nine since then and are boosted by Lionel Messi's return from a hamstring injury.
Xavi, who was rested for the Getafe fixture, was delighted to see Messi back on the field ahead of a game he feels could prove crucial in deciding the destination of this year's title.
"It was an impressive return and (Messi) has clearly come back hungry and motivated," Xavi told Barcelona's official website.
"The game against Atletico is vital for the outcome of the league - it might not turn out to be definitive, but a win would lay down a marker."
In the last 20 years, Atletico and Barca have met as the sides ranked first and second in the table on only three occasions, with the men from Spain's capital winning two of those meetings.
Atletico midfielder Koke has warned his team-mates not just to focus on FIFA Ballon d'Or candidate Messi.
"If he plays we have to be careful because he is the best in the world but Barcelona have great footballers and we must be aware of them all," said the midfielder, who scored the winner in Atletico's 1-0 victory at Malaga last weekend.
"It will be a very important game because the top two teams in the league play, (but) it is just another game and the whole second half of the season is to come.
"We know that to date it is the most important game."
