Quique Sanchez Flores believes it may be too soon for Manchester City to win the Premier League under Pep Guardiola and has tipped Jose Mourinho to get it right at Manchester United.
City are faltering after an impressive start to Guardiola's tenure, losing at home to title rivals Chelsea and away to champions Leicester City in their last two Premier League matches.
The characteristic insistence of the former Barcelona and Bayern Munich coach on playing possession-based football and employing a high defensive line has met with criticism in some quarters.
Speaking to Omnisport ahead of Watford's trip to face City on Wednesday, former Hornets manager Flores suggested Guardiola needs time to get his message across.
"I'm sure that in England the style is not difficult for Pep because in England people love when players play well with the ball," he said.
"Now there are different cultures ... different personalities. Football has changed a lot in the last years in England but the problem is not the style of football.
"I'm not sure Manchester City have enough to be champions. They are young, they are starting to learn the new style so maybe I think it's a bit early to say they can win the league."
Mourinho has also been searching for consistency after taking over at Old Trafford, with United sixth in the table, already 13 points behind leaders Chelsea.
"I'm not surprised that he's struggling because when you have a manager that has a method he needs time for the process [to be implemented]," Flores, now coach of Espanyol, added.
"He knows what he wants to achieve, so he needs time. The worst thing is when you train and you don't get the result because when you win you say 'ok, I got the result', but when you lose, you say 'I want to win now and have to get good results'.
"When you don't have a base [foundation] it's really, really difficult. For sure he knows what is the way [he wants to play] and he is confident in the process. [He has] a lot of different players also. It wasn't easy for Louis van Gaal also, so he needs time."