Extract from new book about Pep Guardiola's first season in charge of Bayern Munich

"You can write about everything you see and be as critical as you like in the book, but during the season please don't talk to the outside world about what you witness inside" Those were the words from Pep Guardiola,one of the most successful football managers of all time, to Marti Perarnau in 2013, when he stunned the Spanish journalist by giving him complete behind-the-scenes access to his first season in charge of Bayern Munich. Over the next year, Perarnau would be privy to every training session and team-talk, an unprecedented level of insight into one of the world's biggest clubs which he chronicles in a new book,Pep Confidential: Inside Guardiola's First Season at Bayern Munich. In this extract, Perarnau witnesses Guardiola's late-night celebrations after his team sealed the Bundesliga title in March, a record for any of Europe's top leagues - and the manager's ruthless dedication as he immediately plots further victories