Jose Mourinho said Chelsea had produced the "perfect" performance after a 5-0 win away to Swansea City saw them extend their lead at the top of the Premier League . Oscar and Diego Costa scored twice each in the first half at the Liberty Stadium to leave Chelsea 4-0 up before the break and substitute Andre Schuerrle added a fifth goal 11 minutes from time. "It was a perfect performance," said Chelsea manager Mourinho, whose side made light of a potentially awkward encounter in south Wales. "The way everything went our way was just perfect." It was a perfect performance. The way everything went our way was just perfect Jose Mourinho Chelsea may have scored five goals but their Portuguese boss praised the Blues' defence, adding: "I thought the team played very well. JT [John Terry], [Branislav] Ivanovic, they all played well. They were solid defensively and the team showed real ambition. "The team has a clear identity. Sometimes you have good teams who play well, but without a clear identity. This team has been going in a certain direction and with a certain identity. "However, I keep saying that if you play fantastically well, but don't win cups, in 20 years time nobody will remember you. Yes, we are playing well, but we have to win competitions. "It's a young team with many years in front of them," said Mourinho. "However, we are trying to make history this season." "Still, I thought we were clever. We pressed them in that area and we were aggressive in recovering the ball." Mourinho insisted Chelsea's latest victory had not made Manchester City's task against Arsenal, who they were playing overnight at Eastlands, more difficult. "I don't think Man City feel pressure. Like them, we have to win every game. We feel the responsibility," he said. Chelsea led inside a minute through Oscar and were rarely tested in a one-sided game, with their display labelled "devastating" by Swansea manager Garry Monk. However, the Swans boss said his side had made life too easy for the visitors. "It was a horrible performance," said Monk. "It was way off the standards we've been used to, especially at home. It is very difficult to make the kind of mistakes we made and to win a game. "We had to be perfect and we were far from it. It was our worst performance of the season and we're all hurting. "To be fair, the fans were magnificent and I'm disappointed for them that we couldn't give them a performance. I can only apologise. It's my responsibility. " Despite this thumping defeat, Swansea remain in the top half of the table and Monk said: "I am not worried about the long-term effect. We have shown in the past that we are capable of reacting straight away and getting a positive result." It was a horrible performance. It was way off the standards we've been used to, especially at home Garry Monk But Monk added he had made his feelings known to his side during the interval. "Yes, I had a few words to say at half-time. I told them they were not doing themselves justice. "I'm sorry we couldn't give Jose a game. He must be very happy."