Manchester City boss Pep Guardiola insists that his side's treble success this season is not enough if he cannot deliver the Champions League to the Etihad Stadium.The Catalan manager’s gaze quickly turned to the challenge of triumphing in Europe next season in the hours that followed his side’s 6-0 demolition of Watford in Saturday’s FA Cup final at Wembley. City became the first English side to win all three major domestic trophies, adding the FA Cup to the Carabao Cup and the Premier League title – but Guardiola acknowledged that, ultimately, his time in Manchester will be defined by whether or not they land the continent’s biggest prize. “I said before that I know we will be judged at the end on whether we win the Champions League,” he told reporters. “I know unless we do that, it will not be enough. This comes with me, I know that.“I arrived in Barcelona, we were lucky and we won it two times in four years and the people expect I am something special and that we have to win the Champions League. That’s still true.“Even at this club, getting the points record last season and winning all these domestic competitions is incredible.”Having narrowly missed out on a place in the Champions League semi-finals following an away goals defeat to Tottenham, Guardiola accepts that Europe’s ultimate prize is the one glaring omission in City’s bulging trophy cabinet.   And while he freely admits the competition remains the most challenging of all, the 48-year-old former Barcelona and Bayern Munich boss hasn’t taken his eye off the task despite his side’s domestic bliss. “The Champions League we don’t win quite so often compared to the other ones because the teams are so good. The competition is so demanding.“But we want to win it, and I wouldn’t be here next season unless I believed we could improve as a group.“We need to continue to try to play well and to arrive at the later stages of competitions, fighting.“That is what I want, that is my target for the next season, to keep this spirit. I know it will be difficult because people will compare us to this season.“People cannot expect us to repeat the treble or win four titles in one season, that is something one team does once in their lifetime.”City’s playing squad and backroom team will parade their trophy haul, which also includes the Community Shield, on an open-top bus tour on Monday evening.“I’m so tired, but I’m so happy,” Guardiola said. “I’m incredibly happy, but exhausted and that is the truth.“I need to keep my energy a little to do our parade and our last party of the season with our people… and then go on our holidays.”--