Adam Lanigan: We all know Pep Guardiola’s good, but since when does that guarantee anything?

The long goodbye to Manuel Pellegrini began last night with a 1-0 victory away to Sunderland and City fans and players showering him with praise. Pellegrini has spent much of his time in Manchester having to answer questions about Guardiola taking his job and now it is fact. As of 1^st July, the Catalan will be in charge at the Etihad Stadium.

The perceived wisdom is that City have landed a real coup. Guardiola would have perhaps headed the list of any chairman around the world in the search for a new manager. Certainly, Chelsea and Manchester United would have cast jealous looks in City’s direction at luring the most fashionable manager in world football to their club.  Pep’s CV currently makes outstanding reading with five league titles and two Champions Leagues from the last seven seasons (including his sabbatical year in the United States) divided between Barcelona and Bayern Munich. It will surely become six with another Bundesliga crown and he might even add the Champions League with Bayern in May. And those figures are impressive by anyone’s standards.

The reality is that Pellegrini has effectively been the longest-serving interim manager in football history. The two-and-a-half years he has served so far has been a period of keeping the seat warm until the man the City hierarchy really wanted became available. In that time, Pellegrini has achieved a league and cup double, and is still in four competitions this season, which is also mightily impressive. He could win all of them, and that would leave Guardiola with big shoes to fill.

Jupp Heynckes was moved out of the hotseat at Bayern in 2013 to make way for Guardiola’s arrival in Bavaria. But the veteran German coach went out in grand style by winning the treble, including victory over Jurgen Klopp’s Borussia Dortmund in the Champions League final at Wembley.

Up to this point, Guardiola has not been able to replicate the feats of Heynckes, despite having less competition at home with Bayern’s acquisition of Dortmund’s best two players in Mario Gotze and Robert Lewandowski, and his Bayern team being subjected to his own coaching skills. And if Guardiola hasn’t yet achieved Champions League success with one of European football true heavyweights, will it not be that much harder with a club like City still feeling their way among the elite?

One of the great truisms in football is that there are no guarantees. Certain things are more likely to happen than others, but there is no 100% cast-iron guarantee of success. And however good Guardiola’s record up to now, he will face in the summer new challenges that could conspire against him.

For a start, he has no previous experience of English football or the Premier League. It always sounds arrogant to say this, but the Premier League does offer a different set of circumstances. Four or five teams will have aspirations to win the title, while all 20 clubs have the finances to sign good players, who can cause a problem to the very best.

In his first three months in charge of City , Pellegrini lost league matches at Cardiff, Aston Villa and Sunderland as his newness to England was exposed. Look at Klopp at Liverpool this season. He looked the perfect fit when he replaced Brendan Rodgers in October and he has created a great impression but the statistics in the league point to something diferent. Played 16, won six, drawn four, lost six. That screams mediocrity and paints the picture of a man struggling to adjust to his new surroundings.

Louis van Gaal has spent around £250 million on new players in his 18 months as Manchester United boss, but seems incredulous when ‘small’ teams like Swansea, Norwich and Bournemouth have the temerity to take on and expose his team and his ‘philosophy’. How do we know Guardiola won’t suffer similar problems when he pitches up at City?

In Spain and Germany, Guardiola has operated with the core of players from the last two countries to win the World Cup, which has effectively given him all the aces in domestic and European club competitions. Think of Xavi, Andres Iniesta, Carles Puyol and Sergio Busquets at Barca. Manuel Neuer, Thomas Muller, Jerome Boateng and Philipp Lahm in Munich. And don’t forget the best player in the world, Lionel Messi. He’s quite a useful man to have in your side the last time I checked!

City will be a greater test of Guardiola’s capabilities to really construct a team rather than mould the very best players into something extra special. There is a feeling around The Etihad that one cycle of success is coming to the end. Yaya Toure, David Silva, Vincent Kompany and Pablo Zabaleta have been the cornerstones around which City have won two Premier Leagues, the FA Cup and the Capital One Cup in the last four years. They represent this glory era for City, but they will all need to be replaced in the next one or two years and that is not an easy feat.

Look at City’s attempts to make do without Kompany this season and you can see why replacing him permanently will be so difficult. Toure has provided a beguiling mix of skill, power and wonderful passing as a player who always produces in the big games –types like that are few and far between. Replacing him will be a gargantuan task.

And this is where Guardiola will need help from Ferran Soriano and Txiki Begiristain. His two old cohorts from Barca have waited for the day Pep could join them in Manchester. And now it will be their job to provide their man with the tools to make City a domestic and European power. There will be no space for the likes of Javi Garcia or Eliaquim Mangala in the new regime.

With Guardiola’s say-so, you can expect City to be shopping in a superior market this summer. But as Leicester City are gloriously demonstrating to everybody, it’s now how much you spend, but how wisely. I for one, had the Foxes down for relegation this season, so it really does underline you won’t be able to guarantee anything when Pep pitches up in Manchester.