If this was a game Pep Guardiola was worried about, who knows how far Manchester City could go this season.

With the Catalan's football taking hold, and Sergio Aguero in this kind of form, anything is possible.

The Blues' 100 per cent start to the season continues thanks to Aguero's hat-trick, but while that will grab the headlines it should not be overlooked how the home side completely dominated the match and created a hatful of chances by playing some fine football. Yet again.

Borussia Monchengladbach are one of the few sides in the world with a default set-up that can really cause Guardiola's approach problems, but they could not get going at the Etihad Stadium.

The German side caused the Catalan plenty of headaches during his time in the Bundesliga: his Bayern Munich side failed to register a victory in their last four meetings, and only took one point off them last season.

In the build-up to this match the City boss stressed how difficult a test this would be, and gave a detailed explanation of exactly why Andre Schubert's men are so dangerous: they are masters of the counter-attack, Guardiola said, they play with so much intensity it is hard to create overloads in central midfield, he added, and their goalkeeper contributes to their build-up play.

That should sound familiar to regular City watchers. Essentially, Gladbach are a budget version of the big-spending City. But, while Bayern found it increasingly difficult to get the better of them, the Blues had no trouble against a side perhaps thrown off their stride by the 24-hour postponement.

If Guardiola was concerned about the opposition's work-rate, he ensured his own men would not be outdone in the energy stakes. City - who have covered more ground than anybody else in the Premier League so far this season - buzzed around the pitch and got in Gladbach's faces on the rare occasions they did not have possession.

When they did have it, they worked even harder to get the extra passing option in midfield. For much of the season City's full-backs have stepped into the middle to become auxiliary central midfielders, while at Old Trafford on Saturday it was the spare centre-back who would break forward. Tonight, City mixed it up, with both Pablo Zabaleta and Aleksandar Kolarov moving in at times, and Nicolas Otamendi at others.

Claudio Bravo, making his home debut in goal, ensured City started their build-up play right from the back and, combined with that clever movement and energy in midfield, City created plenty of goalscoring opportunities.

Aguero rarely passes up an invitation to get on the scoresheet and his smart goal - from a fine Kolarov cross - got City on their way after eight minutes. It looked like he might have picked up yet another damaging injury 25 minutes in, but after receiving treatment on his knee, he was back on and in place to convert a penalty that was won by Ilkay Gundogan, who looked right at home on his debut.

City picked up where they left off at the start of the second half but Guardiola will probably be disappointed that his players could not find a third goal despite a plethora of opportunities. Yann Sommer was praised for his footwork in the pre-match press conference but he showed his shot-stopping is up to scratch as he kept out a number of City efforts.

None of those, though, were by Aguero. The Argentine, perhaps bemused by his team-mates' profligacy, showed how it's done with 13 minutes left. Put through on goal by Raheem Sterling, he sat Sommer down, tapped the ball round the stricken keeper and rolled it into an empty net. 

The result was sealed long beforehand such was City's total dominance, but that really stamped their authority on proceedings. Both Aguero and Gundogan were taken off to standing ovations before Kelechi Iheanacho added a fourth in stoppage time after some nice work from substitute Leroy Sane.

It was a goal that goes to show that City have options even without Aguero, who now has nine goals in his first five games of the season and is still to serve another two matches of a domestic suspension. 

Guardiola wants him to up his work-rate, too, just in case defenders and goalkeepers were not scared of him enough already.

That, though, is why City's decision makers worked so hard to make Guardiola their new manager. No matter how good things look, he always demands more. 

City's games against Barcelona will likely decide who tops the group and there is no doubt that they are firmly in their stride after last night's thrashing of Celtic.