José Mourinho has reignited a simmering rivalry with Manuel Pellegrini by mocking the Manchester City manager's faux pas in the Champions League earlier in the season, when the Chilean failed to realise that his side could have topped their group with a single goal.
City, who play Chelsea in a crunch encounter at the top of the Premier League on Monday evening, were leading Bayern Munich 3-2 in Germany in December and would have qualified as group winners on goal difference had they added a fourth. However, Pellegrini has since apologised for being unaware of the mathematical permutations, bringing on Jack Rodwell in the closing stages of the match.
City lead Chelsea by three points and have a far superior goal difference but have been drawn against Barcelona in the last 16 of the Champions League. Mourinho, who succeeded Pellegrini as manager of Real Madrid in 2010 and irked the South American with his zealous celebrations after Chelsea's 2-1 victory over City earlier in the campaign, claimed the Manchester club would not be regarded as a great side until they had triumphed in Europe.
"They won one title, they won a couple of cups. Only in Europe they didn't do well. Speaking objectively they did very bad in the Champions League in previous seasons, also in the Europa League they did bad," said Mourinho. "The first thing to be successful in Europe is to know the rules of the competition, that's the first thing."
Asked if there was any ongoing feud with Pellegrini, whose achievements at the Bernabéu Mourinho questioned after taking charge of the Spanish club, the Portuguese added: "I didn't fall out [with him]. Not me, maybe him, not me."
Chelsea go into game in good form, having not lost a league game in eight outings and looking cohesive in attack, despite a goalless draw with West Ham on Wednesday. City, however, have scored 29 times in their past seven and crushed Tottenham 5-1 in midweek.
Mourinho, who insists his Chelsea side will only be title contenders next season after a year of progression, admitted he has been impressed by City's attacking "efficiency" but claimed he was enjoying rebuilding. "I enjoy to build a team, build for the future. I enjoy not to be working just for today and next season to start again with another team, spending a lot again of money again, selling a lot of players, bringing in a lot of players," he said.
"I'm enjoying this very, very much. To be the underdog I don't enjoy, I think I'm going to enjoy more next season where I am going to give sequence to the work we are doing."