Manchester City 4 Borussia Monchengladbach 0

Sergio Aguero netted a second hat-trick in as many Champions League games to ensure Manchester City started their Group C campaign swimmingly with a 4-0 win over Borussia Monchengladbach, a day on from torrential rainfall putting paid to the initial fixture at the Etihad Stadium.

The 24-hour delay gave City boss Pep Guardiola further time to consider his failure to beat Borussia in any of his final four Bundesliga attempts with Bayern Munich, while his current club had not won their opening home Champions League group game in five previous attempts.

Those unflattering statistics rarely looked like being extended after Aguero - currently serving a three-match domestic suspension for an elbow on West Ham defender Winston Reid that the Football Association described as "brutal" earlier on Wednesday - converted Aleksandar Kolarov's eighth-minute cross.

The 28-year-old scored a penalty before the half hour and, as City looked like failing to turn their second-half dominance into further goals, he completed a treble to sit alongside the one he claimed in last month's 5-0 win over Steaua Bucharest 13 minutes from time.

Aguero's replacement Kelechi Iheanacho built on his goal Saturday's Manchester derby win by netting in stoppage time to crown a tale of total domination for Guardiola's men - something generally beyond previous City vintages in Europe.

There were some deft early touches from Ilkay Gundogan, making his City debut with David Silva absent from the matchday squad, but there was nothing overly intricate about the hosts' early opener.

Raheem Sterling held up play for Kolarov to thunder a low cross towards the near post, where Aguero prodded high into the net.

Borussia were soon cut open again as Christoph Kramer failed to cut out a Fernandinho throughball and Kevin De Bruyne crossed for Aguero.

The Argentina star's touch unusually deserted him in the box and the ball broke to Gundogan, who should have done better than allowing Yann Sommer to save away to his left.

Any momentum Andre Schubert's side were building from some encouraging play midway through the first half clattered to a halt when Kramer lunged in on Gundogan in the 27th minute right on the edge of the area to concede a penalty and earn a booking. His forgettable outing would end by being substituted before the break.

Aguero stepped up to send Sommer the wrong way to double the lead and the Borussia goalkeeper was then forced to keep out a stinging Gundogan drive.

Sommer's opposite number Claudio Bravo denied Lars Stindl sharply in the 42nd minute, although the home debutant would remain largely untroubled thereafter.

Four minutes into the second half, Sommer fumbled a deflected cross from Jesus Navas, but made amends with a magnificent reaction save to deny Aguero his hat-trick after Sterling kept the ball alive.

There was a relentless feel to City's football as the match passed the hour as they zipped the ball around stylishly and pinned Borussia inside their own half.

Sommer was responsible for it not becoming a chastening evening for his team-mates, as he outwitted Sterling in a one-on-one and denied Aguero once more.

But the prolific marksman would have the final say in that particular duel, as he streamed on to Sterling's pass and rounded the goalkeeper to add to his burgeoning collection of Champions League matchballs.

City's complete mastery of the contest was summed up by Bravo lobbing the ball over Thorgan Hazard to start the move that ended with Iheanacho being set up by fellow substitute Leroy Sane to score from close range.

Key Opta stats:

- Sergio Aguero has scored nine goals in five games in all competitions for Pep Guardiola’s side this season.- Borussia Monchengladbach have won only one of their seven away games against English clubs in all competitions – against Arsenal in the UEFA Cup in September 1996 (3-2).- Aguero is only the third player to score two hat-tricks for English clubs in the Champions League (after Michael Owen and Andy Cole).- Kelechi Iheanacho has scored 16 goals in just 1351 minutes of action in all competitions for Manchester City – averaging a goal every 84.4 minutes.