Pep Guardiola believes it will be impossible for Manchester City to repeat last season’s treble. City became the second club to win the Premier League, Champions League and FA Cup and Guardiola, who won an equivalent treble with Barcelona in 2008-09, moved to dampen expectations before his team begin their title defence at Burnley on Friday. “It’s once in a lifetime,” he said. “I said to the players: ‘Forget about it. We climbed the highest mountain last season with what we have done.’ But the last two days we came down from the mountain and we start from there, everyone with the same intention. There will be a lot of difficulties to climb the mountain as high as possible – we’ll see. “Our football, our behaviour, our mentality will dictate how the season will be. In football, in sport, what we have done remains in our hearts and our minds, how nice it was, but it’s over. Every season we start from zero again but history speaks for itself when you achieve something that we have done – it’s almost impossible to repeat. “We have to be aware of that and hopefully our fans, like ourselves, can understand how difficult it was and so we just try to do a good performance at Burnley, and after Newcastle, and after Sheffield [United]. Game by game, no more than that.” Last season, Erling Haaland scored 52 goals in 53 games but Guardiola will not put pressure on him to repeat this. “I will advise him, don’t pressure yourself too much on [scoring] goals,” he said. “I [previously] said to Erling: ‘Come back at your best, physically and mentally. If you score, fine. If you don’t score, fine. Try to improve in your details, in your quality and skills, and the team will help you as much as possible to score goals.’ “I don’t want Erling to score 50 or 60. Just try to be happy like he was last season and relax.” Guardiola wants the squad and his coaching staff to motivate each other: “We have to challenge ourselves. If people expect I’m the only one who has to do it, this would not be possible. Let’s go step by step. Recover who we are. This job is short. Use every season as an opportunity.” The manager said Josko Gvardiol, City’s new £77m defender, is available.