Real Madrid coach Jose Mourinho hit out at the referee for not sending off Barcelona defender Dani Alves in the Clasico draw at the Bernabeu.
Madrid are now eight points adrift of Barca with only six games remaining in the season, and the Catalan side also boast the better head-to-head record against their bitter rivals having won 5-0 at the Nou Camp earlier this season.
Madrid did well just to claim a point after losing Raul Albiol to a straight red card in the 52nd minute in the incident which allowed Lionel Messi to put Barca ahead from the penalty spot.
However, Mourinho believes it could have been a different story if referee Cesar Muniz Fernandez had also dismissed Alves after his foul on Marcelo inside the area allowed Cristiano Ronaldo to net an 82nd-minute equaliser from the spot.
"I don't understand the reason why Dani Alves hasn't seen a second yellow after conceding a foul in the area for a penalty," said Mourinho.
"I asked the fourth official why there wasn't a second yellow and he told me 'it's because he's a full-back'.
"When everyone thought they could destroy us playing with one player more, for 45 minutes the team was strong enough to compete and strong enough to get a result, and if the referee gives, as he should have done, a second yellow card to Alves, the last 10 minutes playing 10 against 10, it could have been a different story.
"We played very well with 10 players. We played with a lot of dignity and character and with the fans absolutely fantastic, and we almost won."
He added: "In my opinion it was a very even game when it was 11 against 11. In the first half the teams respected each other, knowing they were facing strong opponents. There weren't many great chances, some for them some for us, but not many.
"Afterwards, with 11 versus 10, it was practically mission impossible. It would be mission impossible for many teams, especially against a side who are the best in the world at keeping possession.
"But once again we've been left with 10 men, a lot of time with 10 men, and once again there's been an absolutely incredible difference of criteria."
Saturday night night was not the first time Mourinho has found his teams down to 10 men against Barca.
In losing 5-0 at the Nou Camp in November Madrid had Sergio Ramos sent off late on, while last season when Mourinho was in charge of Inter Milan the Italians lost Thiago Motta to an early red card.
"I'm a little tired of playing against Barca with 10 players," said Mourinho, who also refused to answer questions from certain members of the media following Friday's press walk-out.
Scores of journalists, mainly from the local press, left the room at the club's Valdebebas training ground just prior to Friday's pre-match press conference after Mourinho's assistant Aitor Karanka was sent out to field questions in place of the Portuguese.
The draw was the first of four meetings between the two Spanish superpowers in the space of 18 days.
The bitter rivals also meet in the Copa del Rey final on Wednesday, and then clash in the Champions League semi-finals.
While Madrid may have gained a psychological boost heading into the cup final, tonight's result means Barca are now within touching distance of a third successive Primera Division title.
Barca coach Pep Guardiola insists there is still work to do though, saying: "We're still not champions with 18 points to play for against teams who are playing for their lives.
"We're happy. To come here and not lose is a good result. Madrid are a top team."
With regards to what he can build on ahead of the cup final, Guardiola added: "You always learn something for the next game, we are going to learn how to attack them better and how to control their counter-attacks better.
"But it's a final and millions of situations can happen."
