Roberto Mancini has hit back at Sir Alex Ferguson for his criticisms of Manchester City's European record.
City bowed out of Europe's premier club competition without winning a game in what was statistically the worst performance by an English club since UEFA introduced the group stage format 20 years ago.
Ferguson said it was "unhealthy" for City to have such a poor record in the Champions League, but Mancini pointed out that he had won the Premier League title in his second full season at the Etihad Stadium while it had taken Ferguson six and a half years to make United champions after his appointment in 1986.
United did not win the Champions League for the first time under Ferguson until 1999, in what was his 13th season at Old Trafford.
"Ferguson won his first title after seven years and his first Champions League after 14 [actually 13] years," Mancini said. "I have another 12 years to win a Champions League."
Mancini also denied he is under greater pressure from City owner Sheikh Mansour and chief executive Khaldoon al Mubarak to win the Premier League after City's European failure.
"I don't know this," he said. "You need to ask him [Sheikh Mansour]. I am happy with my job in two years here."
City became champions for the first time since 1968 last season, pipping United on goal difference after both sides had finished level on 89 points.
But Mancini believes it is harder to retain the title than to win it for the first time.
"This can happen to a young team like us that won its championship after 44 years," he said. "The day after is more difficult because you need to work more. The first thing is to forget everything you did until then and work more, because it is more difficult the second year."
United and City meet at the Etihad Stadium on Sunday in the first derby of this season, and Mancini said his rivals' tradition of winning trophies made them favourites.
"When you play against a team that won everything in the last 20 years, you can't change it in two years or three years and you need more time," he added. "For this reason, they have a small advantage."