Sergio Aguero has confirmed that he will be leaving Manchester City when his contract expires this summer. 

The Argentine will leave the Etihad Stadium as one of the greatest players to grace English football, and his legacy will be immortalised thanks to his iconic last-gasp winner against Queens Park Rangers in 2012. 

In the context of modern day transfers, the £38m City paid Atletico Madrid to secure his services is one of the finest transfer masterstrokes of the Premier League era. 

That's easy to say now that Aguero has established himself as the highest scorer in City's history, but he effectively justified that sizable fee within his first 31 minutes of Premier League action. 

Despite spending his summer months at the 2011 iteration of Copa America, Aguero was named on the substitutes bench just eighteen days after signing for the club as City got their league campaign underway against Swansea City on August 15. 

There was a palpable feeling of expectation at the Etihad Stadium.

Signing a player of Aguero's calibre and reputation was still a novelty for a club in the early stages of their transition from noisy neighbours to global superpower. 

The supporters eagerly anticipated his introduction into proceedings. In the 59th minute, just two minutes after Edin Dzeko had broken the deadlock, Roberto Mancini withdrew Nigel de Jong and sent Aguero into the fray.

He was greeted with a heroic reception and opened up his account just nine minutes later with a poacher's finish at the back stick to convert Micah Richards' excellent cross. Lift off.

Just three minutes later, Aguero was at it again. In an incredible moment of improvised genius, Aguero lofted the ball over the onrushing Michel Vorm and, somehow, managed to meet the ball on the volley before it crossed the touchline to square for David Silva to fire into the roof of the net. 

The impression was made. Fans were astonished. But he wasn't finished. 

In the 90th minute, Aguero capped his performance in stunning style by crashing home a long-range effort from 30-yards to secure a 4-0 win for City on the opening day. 

It was a debut that lives long in the memory on the blue half of Manchester and, naturally, it dominated the post-match discussion across the footballing world. 

Joe Hart and Vincent Kompany stepped up to be interviewed by Sky Sports in the aftermath of proceedings and were asked about Aguero's debut. 

"We'll talk about the result and the performance in a minute, but Sergio Aguero, discuss," said the interviewer. 

"He's decent isn't he," said Joe Hart, who was visibly delighted by the new forward's cameo.

"He's come in and £38m is a big price-tag, and £38m well spent. We've not really seen much of him, the manager's kept him quite well protected, obviously he's had a big summer. 

"We've got the likes of Sergio coming in and David Silva's got to get a mention as well in that decent catchphrase." 

The interviewer went on to ask Kompany what he thought of Aguero in training and pondered what the striker would be capable of once he returned to full fitness following a hectic summer with the Argentina national side.

"He's definitely come in with a surprise. He's got great potential. The most important for me is that also you saw some moments of him defending and being hard on the man. 

"For us, for the team, for the season, he's going to be very important." 

The first chapter in Aguero's storied City career was befittingly breath-taking and it's clear from the reaction of Hart in particular that the players knew what a gem they'd secured. 

It was a prescient sign of what lay ahead. 

He was unstoppable that evening and not much has changed since.