It was almost the sort of dream start he had imagined. A Camp Nou with unrestricted entry for fans. A brilliant Barcelona No 10 producing a stunning early goal, to add to the brilliant late goal he had scored in the previous home game. And a booming, affectionate chant of ‘Kuuun!’ around the ground for the new signing. Sergio Aguero understood straight away on his Barca debut on Sunday that his new constituents are immediately on nickname terms. Here, he is <a href="https://www.thenationalnews.com/sport/football/2021/10/31/sergio-aguero-what-happened-to-barcelona-striker-and-why-was-he-taken-to-hospital/" target="_blank">‘Kun’ Aguero more than he is ‘Sergio</a>’, and although, at 33, he will not have time to develop the same deep, enduring relationship with supporters as he did through a transformative decade at Manchester City, he hopes there will be moments that write Kun’s name indelibly into Barcelona history. Aguero’s three minutes off the bench in the <a href="https://www.thenationalnews.com/sport/football/2021/10/18/barcelona-player-ratings-v-valencia-memphis-9-ansu-fati-8-philippe-coutinho-7/" target="_blank">3-1 win against Valencia</a> marked his full recuperation from a stubborn calf injury that prevented any competitive action since he came on in the late stages of the Champions League final in May, the last of his 390 appearances for City. In the five months since, he has known excitement, beginning a new adventure in Catalonia; then shock, when he learnt Lionel Messi, one of the main drivers of his move, was to leave the Barca No 10 jersey and Camo Nou; and then the exasperation of sitting out injured while Barcelona lurched through limp Liga performances and plunged into a crisis in the Champions league. Aguero’s role on Wednesday night will be much like his role in Porto in May, when City saw Chelsea dampening their Champions League ambitions in the final. Only the rescue mission now is to scrape his team off the bottom of a group. Barcelona take on Dynamo Kiev on the third matchday of a campaign that has so far yielded two 3-0 defeats, to <a href="https://www.thenationalnews.com/sport/football/2021/09/16/teen-spirit-not-enough-for-barcelona-in-bleak-champions-league-defeat-to-bayern-munich/" target="_blank">Bayern Munich</a> and <a href="https://www.thenationalnews.com/sport/football/2021/09/30/ronald-koeman-on-brink-at-barcelona-after-benfica-thrashing/" target="_blank">Benfica</a>, and not a single Barca shot on target. “It’s a must-win. If we don’t win, we’ll be almost out,” said Aguero. “But we’re confident and we’ll have the help of the supporters to get the three points.” He felt the confidence, along with 45,000-odd loyalists, on Sunday. Before they united to roar on Kun’s debut, they had gleefully celebrated the teenager now wearing Messi’s old jersey, Ansu Fati, who, like Aguero, has only recently come back from a long period of injury. On his return in late September, <a href="https://www.thenationalnews.com/sport/football/2021/09/27/ansu-fati-wearing-messis-no-10-shirt-scores-on-return-after-10-months-out-in-pictures/" target="_blank">Ansu scored after 10 minutes as a substitute</a>. Against Valencia, his first start since sustaining ligament damage last year, he scored after 13 minutes. Ansu, said Aguero, is to be treasured by Barcelona, who hope in the coming days to sign a new long-term contract with the prodigy. “He’s young and we’re here to help him keep growing and do our best to make him feel as comfortable as possible,” said Aguero. “We all see him in training. He’s not the sort of talent you see every day. We need to make the best of that, because he’s one of ours.” As for Ansu’s assuming the No 10 jersey after Messi’s abrupt departure for Paris Saint-Germain, Aguero made it clear he had not stood in the way of the youngster’s claiming it. Aguero wore the number for City, but is happy with the 19 on his new Barca shirt. “It was a decision I took when I signed because 19 is the number I wore at the under-20 World Cup [in 2005, when his Argentina won] and also in the full Argentina team. Leo had the 10 and when Gerard Pique and others at the club suggested I took it over, I had already asked for number 19. The 10 suits Ansu, and I'm very happy he has come back so strongly.” As for the original, the greatest Barca No 10 of all time, Messi’s departure in late July was a “surprise,” admits Aguero. “That’s in the past now and it came as a surprise to all of us. But I prefer to think about the future. He’s happy, and as his friend I want that for him.” Aguero is meanwhile impatient for his first Barcelona start, to become the leader of the attack of the post-Messi era. But he is reluctant to set a target for the number of goals he might register in his debut season for his new club. “I never set specific targets except to finish a season in the best shape,” he said. “If that means goals, all the better. My aim is to be strong the whole of the rest of the season, score some goals if I can, and win a trophy.”