Jose's unhappy Porto return

Having lost just a handful of games over the last two-and-half seasons, he is reluctant to pick up the habit.

He said: "I cannot be pleased to lose because I am a professional. My players were happy with the draw and looked comfortable but Porto had extra motivation.

"The night was a big sensation for me. I worked very hard to detach myself and did my best to win the game. It's a special stadium for me because for two years it was mine. I tried to come here to win and I am frustrated we lost."

Chelsea will have no shortage of motivation on Sunday when they face Arsenal at Highbury, and Mourinho is confident there will be no hangover from this defeat. He said: "I cannot see a negative relation between this game and the Arsenal game. If I could see that relation then I would've played the team that will start against Arsenal, including Claude Makelele and Arjen Robben. There will be no negative influence from this defeat.

"The players will have today off and from Thursday we will concentrate on the game at Highbury. Arsenal and Chelsea are the top two teams and it will be fantastic. The world will be watching and we want it to be a good spectacle."

The bad news for Arsenal is that Chelsea tend to react rather spectacularly to setbacks.

After losing at their first game of the season, at Manchester City in October, Chelsea went on to win eight successive matches, turning a five-point deficit to Arsenal into a five-point lead over the champions. They will be aiming to put together a similar run over Christmas and New Year.

Chelsea midfielder Frank Lampard said: "Every defeat hurts and we're used to winning. It hurts to lose, especially to a goal like that when we didn't really fill in and had some opportunities to win the game. We don't like losing games and picked a strong team to win the game.

"We're all angry after defeats, including the manager, but we can see the bigger picture. It doesn't change the Champions League situation and we've got a more important game on Sunday.

"We're confident we can go to Highbury and get a result. We went on a great run after losing at Manchester City and that's what we want to do again. We've got a mentality at the club where we can string wins together and will continue to do that."

For a self-styled deity, Mourinho responds well to signs of his own mortality - and there are plenty of lessons to be learned from this defeat. After engineering a 4-0 win over Newcastle on Saturday, with a second-half switch to 4-4-2, Porto provided compelling evidence Chelsea function best when playing 4-3-3.

As the game progressed, the lack of width in Mourinho's midfield diamond became all-too apparent, with the home side sweeping forward in increasing numbers that eventually told.

Damien Duff 's sparkling 54-minute cameo also emphasised his importance to Chelsea. The Republic of Ireland international, overlooked recently due to the sensational form of Robben, opened the scoring after 33 minutes with a wonderfully-taken individual effort, a worthy tribute to his rare mixture of tenacity and talent.

Duff 's replacement, by an unusually disappointing Robben, enabled Porto to gain a foothold in the game and six minutes after his introduction they equalised, Diego volleying home after Giourkas Seitaridis's shot was blocked by John Terry.

Lampard had two good chances to win the game soon after but Porto finished more strongly, with Benni McCarthy outjumping Gallas to take the holders through to the next round.

Arsenal can take heart, but Chelsea are unlikely to play so poorly on Sunday.