Real Madrid coach Carlo Ancelotti admits Atletico Madrid were deserving victors after they handed him his first defeat in charge with a 1-0 win at the Santiago Bernabeu. Gareth Bale finally made his home debut for Real as a second-half substitute, but Diego Costa was the star as he scored the only goal of the game after 11 minutes to maintain Atletico's perfect start to the season. And despite Diego Simeone's men sitting back and defending their lead, Ancelotti accepted they still had the better chances to score a second. "Atletico Madrid deserved to win. They were very defensive but they scored a goal on the counter-attack," he said. "They showed they are a very organised team with a lot of quality." It was the fourth time in seven league games that Real had fallen behind early on and Ancelotti is determined that they start games better and inject more speed into their play. "I think we had the same problem as in the other games. Our build-up play is slow and when the ball arrives further up the pitch there are no spaces to look for a positive solution. "When you play against a team with good defensive organisation it is more difficult and the goal made things even harder for us. We started very well in pre-season but over the past week we have had two very bad games. We need to have better attitude and concentration." Victory for Atletico sealed their best start to a league campaign with seven consecutive victories. They are tied at the top of the table with Barcelona on 21 points, five clear of their Madrid rivals in third. However, Simeone still believes that Real and Barcelona's strength in depth throughout the course of the season will prove too much for his side. "In the long term, throughout 38 games, the financial power and individual quality that Barcelona and Real Madrid have is superior to us," he said. "We have our own strengths and we try to give everything we have in every match. We are working well and at the moment for are being rewarded for that work as a team." We started very well in pre-season but over the past week we have had two very bad games Carlo Ancelotti Costa scored his eighth league goal this season, putting him level with Lionel Messi, and, together with Spain midfielder Koke, was one of the best players. "We are a tough and competitive team, but there is something we do not negotiate on: hard work, and no individual player is more important than the team," Simeone said, when asked about Atletico's leading duo. Barcelona ensured their best start to a Spanish league season thanks to a 2-0 win at Almeria, but the victory came at a cost as Messi was forced off the pitch with a thigh injury. Messi had fired the visitors into a 21st-minute lead with a sensational piece of play as he cut inside two defenders before curling the ball in off the far post from 20 yards. However, the Argentine had to be replaced six minutes later due to a hamstring problem and will now miss Barcelona's Champions League trip to Celtic tomorrow. Barca said he will be out for two to three weeks with an injury to his right leg. In addition to the Celtic match, he will also miss two Spanish league games against Valladolid and Osasuna.