Barcelona: Manchester City manager Manuel Pellegrini said his single season at Real Madrid was the "most painful" period of his coaching career and criticised the club's transfer policy when he was in charge.
City face Real Madrid next Tuesday in a Champions League semifinal first leg, offering Pellegrini a chance of revenge against the team he coached in 2009/10.
Under Pellegrini, Madrid were knocked out of Champions League in the Round of 16 by Lyon and the first round of the King's Cup by Third Division outfit Alcorcon, and finished second in La Liga to Barcelona.
He was sacked in the summer, replaced by Jose Mourinho.
"My time at Madrid was the most painful. The team was not complete, it was still in a phase of formation and had some evident problems," Pellegrini said in an interview with Spanish newspaper Marca.
Madrid spent 257 million euros ($289 million) on players in the summer of 2009 when Pellegrini took over, including Cristiano Ronaldo, Karim Benzema, Xabi Alonso and Kaka.
However, the Chilean coach criticised the sales of winger Arjen Robben to Bayern Munich and midfielder Wesley Sneijder to Inter Milan.
"The frustration made me think about resigning in pre-season," said Pellegrini.
"We had a lot of strikers and too few midfielders. It was not a team to win the Champions League."
The coach also said he had no relationship with the Madrid board and president Florentino Perez.
"I knew they were going to sack me since I arrived, since August. Not after Alcorcon or the Champions League elimination. I had no relationship with the board," he added.
Pellegrini said he had no hard feelings with City for hiring Pep Guardiola for next season, but said the announcement may have affected City's Premier League form.
City have won five, lost four and drawn two games since Guardiola's appointment was announced on Feb. 1, but have reached the Champions League semi-finals for the first time in their history.
City are fourth in the Premier League on 61 points, 12 behind leaders Leicester City.
"I knew I had three years on my contract with City and I have completed them. Another thing is whether the uncertainty affects the mentality of the players when they're competing, when you speak about who's coming in and who's leaving," he said.
"City have always wanted to hire Guardiola. If I had won two Champions Leagues and two Premier Leagues, Guardiola would have arrived anyway." - Reuters