Manchester City made this second leg appear a different sport. One in which they swept into the quarter-finals by reducing Borussia Mönchengladbach to extras in a supreme show of total, ruthless dominance. By 18 minutes the tie was over. City were 2-0 ahead, 4-0 on aggregate, and this was a training exercise: one for Pep Guardiola’s side to continue forming the pretty passing patterns that presage the killer touch before goal. If this ascendancy made it some surprise the score was not increased – Riyad Mahrez spurned several late chances as they continued to press – now comes the defining moment for manager and team. Guardiola has never led City beyond the Champions League quarter-finals but whoever they are paired with in Friday’s draw their formidable form – they have not conceded in the competition for 706 minutes and this was a 24th win from 25 outings – and the 50-year-old’s previous failures means serious questions will be asked if they do not roll on to the last four, at least. City join Liverpool, Paris Saint-Germain, Real Madrid, Porto and Borussia Dortmund in the last eight, with two of Chelsea, Bayern Munich, Atlético Madrid and Lazio to be confirmed on Wednesday. Guardiola said: “Now it will be the eight best teams in Europe – the quality will be higher and it’s more difficult but hopefully this team can maintain this mood and we can compete, especially in two games. When you go through you have to deserve it so we arrive there and try to play good and after we will see what happens. “The first day I arrived [in summer 2016], I was told I have to win the Champions League – this is always on our shoulders. I’m not thinking of semi-finals, let’s have a good first game and second game. If you think of what you are going to win you forget what you have to do.” City required only 12 minutes to claim their 100th goal this term. From a right-wing position Rodri passed to Mahrez who relayed the ball to Kevin De Bruyne. The Belgian allowed it to roll past him, then struck a sweet left-foot that pinballed in off Yann Sommer’s bar in scintillating fashion. Six minutes later it was 2-0. Here, the Germans could not live with Phil Foden when he swept through the middle and hit a reverse pass precisely where Ilkay Gündogan wished. The midfielder’s touch was followed by a clinical finish into Sommer’s right corner for a 13th of his standout season. City had the air of a heavyweight in a mismatch against a featherweight: when they wished to stun Mönchengladbach’s senses a flurry of blows were landed. After Mahrez spun and lobbed into Gündogan the latter came close to the knockout punch but at close range his finishing touch was absent. City’s only challenge was whether they could retain focus. A Mahrez foray suggested so and Marcus Thuram’s 20-yard effort while not concerning Ederson was at least a reminder to Guardiola’s side. Really, though, the Catalan has his men so well drilled complacency is unlikely. As half-time approached they went close to a third. De Bruyne’s 30-yard free-kick dipped but was straight enough for Sommer to tip clear. A scare came when Thuram fed Breel Embolo and his shot beat Ederson but not his left post. Yet by the break this had been an exhibition from City: one executed at a stroll. Guardiola ordered his side to keep on hunting in the second half as illustrated by a Rodri barrelling run that had him skating through the centre of Mönchengladbach’s midfield and drawing a foul. De Bruyne flipped the free-kick in but disappointed by not beating the first defender. Marco Rose’s side then tried a deep press as they had at the start but City simply revolved the ball around them, Ederson’s ability to land pinpoint 40-yard angled passes further demoralising their opponent, while later, John Stones was as imperious when anticipating Stefan Lainer’s cross from the right by simply extending a leg. There is an arrogant air regarding how City move forward: it is as if they expect to impress their plan upon the defence before them and nothing can deny this. And they also hunt in a blue pack as when Mahrez dinked in a ball toward Bernardo Silva, a circle of teammates around him offering other options. Inevitably, a phase was entered in which the match meandered. João Cancelo’s earlier booking had Guardiola replacing him with Oleksandr Zinchenko, with Rodri also superseded by Fernandinho. Each was instantly in the groove via an exchange of ping-pong-like passes between them that will not have cheered Mönchengladbach. “They were too much for us,” said Rose.