Pep Guardiola has urged Manchester City to make an “incredible step” towards the knockout stages of the Champions League and record the first success of their season. City host Olympiakos on Tuesday night on top of Group C and with maximum points after beating Porto and Marseille, with <a href="https://www.thenationalnews.com/sport/football/city-thrash-woeful-marseille-to-stay-top-in-champions-league-group-c-1.1100820">last week's 3-0 victory</a> in the Stade Velodrome ticking off a key part of Guardiola's blueprint for reaching the last 16. It is an achievement the City manager believes should not be underestimated as he argued the Champions League has become tougher, due to the greater strength in depth in the competition. Unlike City, Real Madrid, Atletico Madrid, Juventus, Paris Saint-Germain, Ajax and Borussia Dortmund have all been beaten so far, while Inter Milan are yet to win. “It is the Champions League: you cannot make a false step,” Guardiola said. “After that, you struggle. We know to qualify you have to secure your games at home and win at least one away. We did it, winning in Marseille, but now we have to keep the points at home. It is a huge opportunity for us to make an incredible step. “Qualifying for the next round is the first success of the season. It’s not like a decade ago when qualifying was much easier than now.” Guardiola’s explanation for the improvement of other clubs was: “More investment, the managers prepare the teams better, the teams know more exactly what they have to do. "There is more money everywhere, not just in a few clubs. Last season we play against Atalanta and people say: ‘It is only Atalanta.’ They were two minutes from the semi-finals of the Champions League.” Booking their spot in the last 16 early would allow Guardiola to rotate his squad after he said the cramped fixture list is making him more conscious of how many minutes his charges can play. “For sure,” he said. “It depends on the players as well. There are players that can play three four five games in a row, no problem, but others struggle more. November, December and January are very demanding in this country.” Guardiola could have another option to allow him to alter his forward line on Tuesday. Gabriel Jesus, who has been out since scoring in their <a href="https://www.thenationalnews.com/sport/football/pep-guardiola-hails-incredible-phil-foden-after-manchester-city-make-winning-start-at-wolves-1.1081375">opening day win at Wolves</a>, is back in training. City will assess the Brazilian to see if he is fit to make his comeback. They are waiting to see if Sergio Aguero will be able to return against Liverpool on Sunday after a muscular injury. “After the international break for sure he will be ready,” Guardiola added. Raheem Sterling is one of those who has stood in as a striker in the absence of a specialist. Guardiola feels the role only suits him in certain games. “He can play there when the opponents play with a lot of spaces in behind and they come to press, he can do it,” he said. “When a team settle in the box for 90 minutes, he is better on the sides than in the middle.” Guardiola has had more cover at centre-back after the arrivals of Nathan Ake and Ruben Dias. “We struggle a lot last season for the problems we had, Vincent [Kompany] went to Belgium and an important injury for Aymeric [Laporte] and we were damaged,” he said. “Now we have alternatives.” Dias and Laporte have become the first-choice partnership but the summer signing Ake is savouring the battle to earn a place in the team. “We have a lot of competition with so many good players in the squad but I knew that beforehand,” the Dutchman said. “It was always going to be a challenge.”