Pep Guardiola has insisted he will not rip up his gameplan by going on the defensive to win the Champions League and said the key instead is for Manchester City to be better in both penalty boxes. The Catalan, a Champions League winner with Barcelona in both 2009 and 2011, believes fine margins are separating his side from success. And he feels that City have to be more clinical in attack and more watertight in defence, rather than abandoning their current blueprint, if they are to become champions of Europe. City adopted an unusually cautious approach away at Tottenham last season, when they lost 1-0, but Guardiola said that was a one-off and feels his usual strategy is both their best form of defence and attack. “The way we are really strong as a team has been built up from four seasons ago,” he explained. “I don’t like to change something for one specific game. But sometimes you have injuries, you have problems, you have a smell from the team and you have to do it. In that moment we play three days before Brighton in the semi-final of the FA Cup.” City host Atalanta tonight after making a 100 per cent start to Group C, beating Shakhtar Donetsk 3-0 and Dinamo Zagreb 2-0, but they had 20 shots against the Croatian champions and did not seal victory until Phil Foden struck in the 95th minute. “The Champions League will be won in the box and so far we haven’t been very strong in the box,” Guardiola added. “These little margins are sometimes the difference and we’re working on that. I believe that kind of situation is about the mentality. We’re good enough and we’re strong enough and when you play good, you defend less. When your build-up is good, you concede few goals and we conceded few for four seasons. It’s not a case of defending well. If you play well in all departments, you concede really few.” City have exited Europe twice on away goals after conceding three times at home in Guardiola’s reign, with a 5-3 win over Monaco in 2016 and a 4-3 victory over Spurs in April costing them on aggregate. “Two times in the Champions League we went out on goal difference and in both games we conceded a lot of goals,” Guardiola said. “We scored four here against Tottenham and five goals against Monaco, but we conceded a lot. But in this competition, you play against incredible players and if you give some team a metre in one moment, they will score. We have to know that.” City scored 169 goals last season and are the Premier League’s top scorers again but Guardiola, who thought they should have beaten Crystal Palace by more than two goals on Saturday, drew a distinction between the matches when they are prolific and when they are profligate. “Be clinical with a good mentality to score goals,” he urged. “Sometimes it happens. Chelsea last season, six times we arrived [in the box] and six goals. A few weeks ago against Watford it was five times and five goals [in the first 18 minutes]. “In the Champions League, teams don’t have 20 chances. In that moment we were able to do that. The players know you have to play good to create a lot of chances. This season we are not incredibly strong in the box and that is why we have to improve. If not, it is more difficult in this competition against teams from the top level.” Guardiola believes City need six more points to book their spot in the knockout stages. Kyle Walker and Nicolas Otamendi are back in training but unlikely to start against Atalanta, who have lost both games in their maiden Champions League campaign and gave up a 3-0 lead to draw with Lazio on Saturday. However, Guardiola is an admirer of Serie A’s top scorers and their manager, Gian Piero Gasperini, who steered them to third place last season. He added: “I was lucky enough to meet him. What Atalanta did last year and what they are doing this year is incredible. It is a great joy to watch his team play. They are brave. They take a few risks. Atalanta score a lot. Sometimes they concede as well.”