Manchester City reached the last 16 of the Europa League after a 4-0 win over holders Porto at the Eithad Stadium sealed a 6-1 aggregate victory.

Sergio Aguero put the Premier League side ahead on the night after just 19 seconds, but it wasn't until the 76th minute that Roberto Mancini's men were able to kill the tie off completely.

Aguero turned provider for substitute Edin Dzeko to make it 4-1 on aggregate, and to add insult to injury the Portugese champions had Rolando sent off for a second bookable offence in the aftermath with he and several team-mates furious over an alleged foul in the build-up.

Capitalising on the extra man, the hosts raced to a late four-goal lead through David Silva and on-loan midfielder David Pizarro, and will now face either Legia Warsaw or another Portugese side, Sporting Lisbon, in the next round of the knockout phrase.

The holders were already facing a tough task to keep their title defence alive after being defeated 2-1 at home in the first leg last week, and it took City less than a minute to turn the aggregate screw.

A poor attempt at a simple pass from Nicolas Otamendi was cut out by Yaya Toure and sent straight into the path of a forward-running Aguero, who hunched himself low and picked out the bottom far corner to give those home fans who had made the early kick-off reason to celebrate.

City exploited another hole at the back on 16 minutes and almost doubled their lead when Toure got through on goal only for goalkeeper Helton to time his run out well enough to block the shot.

The rebound fell to Samir Nasri who, instead of trying his luck from 25 yards with an open goal at his mercy, tried to play Toure through once again only to trigger the offside flag.

Silvestre Varela had a good chance for the visitors on the break as he moved the ball into the City area from the left-hand side, but Joe Hart matched Helton’s earlier efforts by making himself big and thwarting the shot.

Helton’s eagerness to race off his line wasn’t as wise shortly before the half-hour mark, as in almost an exact replica of the build-up to the opening goal Porto’s tendency to play their way from the back gifted the ball to Aguero.

The Argentine casually rounded the keeper but with some distance remaining between he and the goal, saw his dipping drive come back off the crossbar.

Toure found himself with space and time on the edge of the Porto box on a second occasion three minutes before the break, but lacked the pace and decisiveness to complete the move and eventually could only square for an off-target Aguero effort.

Aguero appeared determined to begin the second half as he had the first, though his square ball to Silva on 48 minutes was cut out by a combination of Maicon and Rolando just before the Spaniard could convert.

A clever quick free-kick from Joao Moutinho teed up Lucho Gonzalez, who recently returned to the club following a spell in the French Ligue 1, to fire narrowly wide five minutes later and James Rodriguez had the ball in the City net on 57 only for the offside flag to cancel the effort out.

Things continued to go downhill for Vitor Pereira’s side as they lost Otamendi to a nasty-looking facial injury around the hour mark when he caught team-mate Maicon’s boot full-force between the eyes as the two simultaneously strived to clear a loose ball.

And with time ticking away, City’s second goal all but guaranteed new champions in the competition this season, with Aguero threading a lovely through pass to substitute Dzeko, who finished first time beyond Helton.

The goal came at the culmination of a counter-attack which Porto felt began with a foul on Hulk, and of all the players protesting the decision to allow the game to continue, Rolando had too much to say for referee Wolfgang Stark’s liking.

Already on a caution, the centre-back earned himself a second yellow card and Porto had 13 minutes to get through a man short.

It was all the opportunity the home side needed to stretch out the scoreline after labouring through the majority of the contest, with Dzeko and fellow sub Pizarro combining well before Pizarro squared for Silva to make it three with six minutes remaining.

And less than two minutes later, Cristian Sapanaru’s challenge inside the area on Dzeko sent the ball onto the feet of Pizarro, who joined Aguero on a goal and an assist in the match with a cool finish into the corner.

Liam Happe - on Twitter @liamhappe / Eurosport