Touré defies his jetlag as Aguero eases City's passage Roberto Mancini had anticipated that this was an encounter that would be "decided over 180 minutes," that it would be won on points rather than with a single knockout blow. However, as the City manager's side slipped into gear here last night, Porto were not just on the ropes but starting to actively slide down them. They are a not a side accustomed to losing in their own stadium, but as Yaya Touré squared the ball beautifully for Sergio Aguero to slide home, it sealed a victory that pushed the Europa League holders to the brink of elimination that will probably be settled in style on the return leg in Manchester. There may be a touch of needle about it, too, as City have said they will file an official complaint to Uefa about racist abuse allegedly directed at Mario Balotelli last night. Frankly, the Manchester City manager would have settled for a draw, especially after going behind. Mostly this was the kind of match he would have enjoyed in the same way a forward defensive push from Geoff Boycott or Jack Nicklaus's short game might once have been enjoyed. It will not feature much in any end-of-season videos but it was reassuring, and in its way mightily effective. The Aguero winner right at the end was a vindication of his game plan. For Manchester City this had been a serious test, though. If Porto are not classed among the aristocracy of European football to which City aspire, they are certainly part of its landed gentry. Since 1987, a year that marked one of City's many relegations, they have won the European Cup twice plus the Uefa Cup (or its equivalent, this Europa League) twice. This may have been a rather lesser occasion but when Silvestre Varela slid in to open up the scoring the dragon banners were unfurled and the songs swept across the stadium as they had done when the side marshalled by Jose Mourinho overcame Manchester United here on their way to the Special One's first European Cup. Mancini's side were wearing the red and black striped shirts in which Milan had destroyed Arsenal the night before but their task here was to avoid defeat rather than inflict one and for the opening 20 minutes they carried out their instructions pretty well. Porto made several attempts to turn City's flanks without ever getting past either of Mancini's full-backs. However, the first time they did, they scored. "Hulk" is not quite the footballing juggernaut suggested by the nickname that Givanildo Vieira de Souza's physique has earned him, and he has never justified the preposterous €100m [£83m] buy-out clause that the Portuguese champions have inserted into his contract. However, like a lot of centre-forwards - Alan Shearer was a prime example - this Hulk is a fine crosser of a ball. The one he delivered as the game creaked towards the half-hour mark was fast and low and Varela timed his run to meet it perfectly as it sped between Vincent Kompany and Gaël Clichy. That was rather less than City deserved. It was a measure of the importance Mancini attached to the night that he chose Yaya Touré. It was both a gamble and a vindication of a man who has glued his side together at its most critical moments. He had flown 5,000 miles from Libreville to Oporto via Abidjan amid the crushing disappointment of the Ivory Coast's failure to win a tournament which was theirs by right and which they dominated. Only those members of the Hungarian or Dutch World Cup teams of 1954 and 1974 would understand quite how Touré felt as he embarked on the long journey home. He began well enough and he was moving away with long strides from Danilo when the Brazilian right-back brought him down and in doing so injured himself enough to be taken off on a stretcher and with a yellow card. Touré had not played in a City shirt since they swept Liverpool away in the first week of January, while this was Balotelli's first game since his four-match ban for stamping on Scott Parker. The hint of rust on the young Italian's boots may have accounted for his failure to pull City almost immediately level. A long ball from Samir Nasri found him with far more time in front of goal that he probably knew he had and though the shot may have stung Helton's hands it was directed too close to the goalkeeper. As the game wore on, City went ever closer. The second half was barely five minutes old when Micah Richards' muscular run ended with the ball slapping against Porto's post and then came the equaliser, the crucial away goal, from an unthreatening ball that Alvaro Pereira attempted to direct into his goalkeeper's arms and succeeded only in steering into Helton's net. If it was a self-inflicted wound then it was likely to prove fatal and perhaps the night's most enduring image was that of Porto's captain, Hulk, whose shot was powerful enough to have injured a team-mate. His final one of the night threatened only a corner flag and the Brazilian sat and pounded the turf in animated frustration. Man of the match Y Touré. Referee C Cakir (Tur). Attendance 47,417. Sporting chance still exists of City meeting Sporting twice came from behind in Poland to earn a 2-2 first-leg draw with Legia Warsaw, with the eventual winners going on to host the victors of the Porto-Manchester City match in the last 16. In Russia, Manchester United's opponents could be Lokomotiv Moscow after they came from behind to beat Athletic Bilbao 2-1, while PSV triumphed 2-1 at Trabzonspor, making the Dutch side favourites to progress to a last-16 tie with either Stoke or Valencia. James Mariner