Chelsea boss Andre Villas-Boas admitted Norwich will not be Premier League pushovers this season.

The Portuguese Europa League-winning boss may have disputed Paul Lambert's take on the second-half penalty incident – but Villas-Boas also paid tribute to Lambert's Carrow Road revolution.

'For a team that came with two back-to-back promotions it shows the quality of work that Paul Lambert is doing and the empathy that they have with the crowd shows maybe Norwich have a role to play in the Premier League,' he said. 'They did that against Stoke and showed that maybe they are a team who can create problems for other teams.

'Every game is different. Norwich didn't play particularly well, but created problems with an objective of direct play and good fighting spirit supported by an excellent crowd. This is their game, their philosophy and it suits them and is perfect for them.'

The 33-year-old was equally impressed with City's attacking adventure.

'It was an intense game. Both teams had a lot of chances,' he said. 'We had the initiative, but Norwich had their share of shots on goal. In my opinion their goal came at the wrong time – unfortunately (Branislav) Ivanovic and (Henrique) Hilario collided to give us 1-1. It made us a bit edgy, but we managed to get the control right and the emotions right. We managed to turn the game around which is fantastic. These games are difficult. I think we showed more consistency in the 90-minute performance because previously we had two good second-halves at Stoke and West Brom.

'There is room for improvement. In the first half, although we had the initiative there were a couple of technical mistakes in the passing and control. That didn't give us a great fluency. Norwich, to be fair, were threatening as well coming out in quick counter-attacks with a lot of objective in their play. We found the spaces better in the second half.'

Didier Drogba's sickening clash with John Ruddy forced a lengthy second-half stoppage. The Ivorian was knocked unconscious before being taken to hospital for a precautionary check-up, but Drogba's replacement, Nicolas Anelka, teed up Ramires in the incident that led to Frank Lampard's penalty.

'He lost consciousness completely and I have to be very, very grateful not only to my players, but the Norwich players and the medical staff to react so quickly to a potentially dangerous situation,' said Villas-Boas. 'I think he was unconscious for a couple of minutes. I haven't seen the incident up close, but it looked like natural physical contact.

'We changed it to 4-3-3 which gave us a bit more quality in our possession. I was very happy that the team was able to control their state of mind and to fight back. We showed a lot of commitment and desire. We started 4-1-3-2 here, so it's good we have that flexibility because sometimes you can be criticised for not having that as a team. We have that.

'When the midweek games start coming in it will help with the fluency of our game. You get more match situations instead of training and in the end it is the games that matter.'

The former Porto boss also believes successfully negotiating the final few days of the transfer window will help his Blues' squad to focus on domestic and European prizes. Chelsea continue to be linked with Tottenham's Luka Modric, but Villas-Boas is only interested in the players at his disposal.

'I think the closing of the transfer window will help to settle the people here,' he said. 'It is a pretty exciting time now. We have to keep calm and if something happens, it happens. (Juan) Mata came in and for someone who only had two training sessions got into some nice positions and showed some quickness.'