Manchester City manager Pep Guardiola said Thursday that last season's remarkable treble success was a "once in a lifetime" achievement as he tried to lower expectations on the eve of a new campaign.

City, bidding to become the first side to win four consecutive English top-flight titles, start the Premier League season away to Burnley on Friday.

They will be favourites for every competition they enter but Guardiola warned against a repeat of last term's triumphs, which also saw City crowned champions of Europe for the first time as well as lifting the FA Cup.

"It feels like it finished yesterday but we start again," Guardiola told a pre-match press conference on Thursday.

"I don't think it will be possible to do what we did last season, it's once in a lifetime. I said to the players forget about it.

"We climbed the highest mountain last season but we have come down that mountain now. We start from the same as everyone else, with the same intention and there will be a lot of difficulties to climb the mountain again."

The 52-year-old Spaniard added: "What we have done remains in our hearts and minds but it's over.

"The history speaks for itself but it is almost impossible to repeat."

Guardiola, meanwhile, refused to comment on speculation linking City, beaten on penalties by Arsenal in last weekend's Community Shield at Wembley, with a move for West Ham midfielder Lucas Paqueta.

But the former Barcelona boss was rather more forthcoming about the prospect of facing a Burnley side managed by his former City captain Vincent Kompany, who guided the Clarets back to the top flight at the first attempt.

"Normally the first games are difficult, especially against newly-promoted teams because they have nothing to lose and the energy, the dream to do a good season," said Guardiola.

"Apart from that, Vinny knows us well and he is doing an incredible job.

"He has changed the way Burnley play completely and they destroyed the Championship. It will be a tough, tough game."

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