Barca have now gone three games without a LaLiga win having picked up five points out of a possible 21, suffering defeats by Leganes and Las Palmas in their previous two home games. They are three points behind Atletico having played a game more.
Pedri sent the Catalans ahead but second-half goals from Rodrigo De Paul and Alexander Sorloth helped Diego Simeone's side move three points clear at the top of the table, having played one match fewer than Barca.
Diego Simeone's red-hot Atletico are one of the most in-form teams in Europe on an 11-game winning streak in all competitions and looking like a well-oiled machine with Antoine Griezmann, Julian Alvarez and Rodrigo de Paul firing on all cylinders.
La Liga leaders Barcelona stumbled 1-0 at home against Leganes on Sunday as they suffered another blow in the Spanish title race.
Diego Simeone's side have been in fine form and continued their winning run across all competitions with a deserved home triumph, pulling provisionally level with league leaders Barcelona.
Real missed the chance to move above leaders Barcelona in LaLiga as they stay second on 37 points from 17 matches, one behind the Catalans who host Leganes on Sunday when Atletico, in third place on 35 from 16 games, welcome Getafe.
The 23-year-old was forced off with a muscle injury in their 4-0 thrashing of Osasuna at the Bernabeu earlier in November
"We changed the position of the forwards, with Mbappe outside and he did well, like Vinicius inside," said Ancelotti.
Raphinha and Robert Lewandowski's goals put the Catalans in a healthy position but Marc Casado's red card in the 82nd minute helped Celta start the fightback to snatch a point.
Real Madrid suffered a 2-1 defeat at Villarreal on Saturday after a goal and assist from striker Gerard Moreno, giving leaders Barcelona a chance to move ahead in the title race.
LaLiga on Tuesday said it has filed charges relating to the racist abuse of Real Madrid forward Vinicius Jr to the "relevant judicial, administrative and sporting bodies", adding that it will step up efforts to identify such abuse in the future.
Real Madrid's Brazilian forward Vinicius Jr on Saturday accused LaLiga of continuing to do nothing about racist fans at matches, after videos on social media showed fans shouting abuse and throwing objects at him at a match a day earlier.
Barcelona's lead over Real Madrid atop the LaLiga standings evaporated on Saturday after they were held to a 1-1 home draw by local rivals Espanyol in a bad-tempered clash in which both sides were reduced to 10 men.
Karim Benzema buried his World Cup nightmare with two late goals as Real Madrid defeated Valladolid 2-0 on Friday to go top of Spain's La Liga.
Striker Robert Lewandowski will be available for Barcelona's match against Espanyol after a Spanish court overturned his suspension, the LaLiga leaders said on Friday.
Atletico Madrid coach Diego Simeone said that he is mainly responsible for the team's situation as they have failed to find their best form and sit in fifth place in LaLiga.
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Toni Kroos scored an impressive volley as Real Madrid beat Cadiz 2-1 to cut the gap on La Liga leaders Barcelona to two points on Thursday.
Real Madrid lost their first La Liga game of the season, going down 3-2 in a battle at city-rivals Rayo Vallecano on Monday to leave Barcelona two points clear at the top.
