© Provided by The GuardianPhotograph: Getty Images
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.
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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 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.
© Photograph: Getty ImagesKevin De Bruyne celebrates the first goal.
Guardiola decided this was a game where neither Sergio Agüero or Gabriel Jesus were required to start so Kevin De Bruyne was the floating No 9. Raheem Sterling also missed out, though he was a replacement, unlike at Fulham on Saturday.
The manager stated after the first-leg win that 2-0 might not be enough but given the playing riches at his disposal and Mönchengladbach's six consecutive losses City were clear favourites. The first half display only enhanced this perspective.
After tapping the ball around to settle in, suddenly João Cancelo was moving inside from left-back, as Guardiola loves him to do. The Portuguese's subsequent chip had Phil Foden clear in on Yann Sommer's goal but his attempted flick-finish disappointed.
City's next attack did not as they claimed their 100th goal this term. From a right-wing position Rodri passed to Riyad Mahrez who relayed the ball to De Bruyne. The Belgian allowed it to roll past him, then struck a sweet left-foot that pinballed in off Sommer's bar in scintillating fashion.
As this was City's "home" leg despite being played in Budapest's Puskas Arena Mönchengladbach still required three to knock them out. That lasted only until the 18th-minute. Here, the Germans could not live with 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.
© Provided by The GuardianIlkay Gündogan pokes the ball past Yann Sommer to end a flowing move and put Manchester 4-0 up on aggregate. Photograph: Getty Images
This start had Guardiola visibly delighted. 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 German came close to the knockout punch but at close-range his finishing touch was absent.
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City's only challenge was whether they could retain a high level of 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. Then, a Mahrez surge left all defenders near him stranded but the Algerian overran the ball.
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 - surely - will have ordered his side to keep on hunting in the second half. Rodri suggested so with a barrelling run that had him skating through the centre of Mönchengladbach 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 first period's start but City simply revolved the ball around them, Ederson's ability to land pinpoint 40-yard angled passes as if using a protractor 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.
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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 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. 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.