For Manchester City, it is the scoreline of their season. There was a pleasing ring to 6-1 long before Porto suffered the same fate as Manchester United. It took 180 minutes, rather than 90, resulted in rather less gloating and came in a competition City would rather have not entered, but it was an emphatic elimination of the Europa League holders nonetheless.
The story of their season, however, involves the contrasting antics of the boys from Buenos Aires. Argentine striker acquired a new meaning in Manchester over the past few months when one forward withdrew his labour, but there are different definitions. Troublesome and the terrific, the rebel and the reliable, the exile and the excellent, Carlos Tevez and Sergio Aguero have been the opposites from the other side of the world.
While the refusenik turned apologist, the guarantee of goals has kept to a truer and simpler path. He was Porto's nemesis, just as Tevez has been the bane of Roberto Mancini's life. His reward for brilliance on the field is to be overshadowed by Tevez off it. The latter dominated the post-match discussion. "I accept his apology," said Mancini. "I don't have any problem. I think Carlos can help us to do a good job in the next two months."
His compatriot has been contributing for the past six. Like David Silva and Yaya Toure, both tremendous again, Aguero has forged a reputation as the anti-Tevez, the low maintenance superstar. Like Tevez last season, he has maintained his standards across a season.
After 19 seconds, Aguero had his 20th of the season - at this rate of progress, 30, a landmark that has eluded Tevez in England, seems probable - and the most important of the night. The trio of late strikes that followed, from Edin Dzeko, Silva and David Pizarro, rubber-stamped progress and provided a harsh impression of Porto's efforts. "The result was a great untruth," said their manager, Vitor Pereira.
The notion that the first goal of the game is the most significant has rarely been truer; it is still more unusual it comes quicker. The second fastest in Europa League history occurred when Nigel de Jong intercepted Nicolas Otamendi's poor pass, Toure's rather better ball found Aguero darting off the shoulder of the last defender and the forward finished confidently.
It provided a model for the game, Aguero's pace, intelligent movement and sharpness enabling City to counter-attack with elegant menace. The Argentine struck the bar with a delightful lob, following Silva's pass, while Toure, released by Barry, had a shot blocked by Helton. On both occasions the Brazilian, who seemed more sweeper than keeper, was outside his box. The latest in a line of eccentric and adventurous Latin American goalkeepers, he was only unbeaten when rather nearer his net.
Each of the three subsequent goals involved substitutes, a sign of Mancini's impact. Often deemed defensive - not least by Aguero's father-in-law, Diego Maradona - he added an attacker when protecting a 1-0 lead and was rewarded when the strike duo combined. Aguero supplied the incisive pass, Dzeko the cool conclusion to the move. Others were rather more fractious, Rolando collecting a second caution for dissent.
City prospered against ten men, the replacement Pizarro setting up Silva and then scoring himself in a profitable cameo. It was an illustration of the playmaker's quality on a night when a more robust midfielder had played his part. Out of favour for much of the campaign, De Jong has added solidity in both legs against Porto. The triumvirate of the Dutchman, Barry and Toure form a physically strong and positionally disciplined triangle.
It was necessary against a side who had much of the ball. "It is not easy to beat Porto, they are one of the top teams in Europe," Mancini said. They certainly were last year, when they went unbeaten in the Portuguese league and won the Europa League. The architect of their success revisited his past, but the curse of Andre Villas-Boas has spread from Naples to Manchester. Even on his night off, the Chelsea manager witnessed his old side adopting his new charges' haphazard approach to defending in the first 20 seconds and the last 15 minutes.
While the first leg pressing showed the merits of Villas-Boas' philosophy, Porto's high defensive line and susceptibility to the ball in behind indicated its perils. Rewind a year and AVB was very much in favour. So, too, was Tevez. Now the striker who has come in from the cold may yet make an unlikely comeback. But with Aguero in this form and with the three major strikers having contributed 49 goals so far, he ranks fourth in a forward line headed by another Argentine.
MAN OF THE MATCH: Sergio Aguero - Razor-sharp and a constant threat to the Porto defence, Aguero was nonetheless the latest subject of Mancini's mantra about anyone under the age of 25. "He is young, he needs to improve," said the Italian. If he does, it will be a frightening prospect for defenders. Vincent Kompany proved a more generous appraisal of his efforts. "The little fella proved to be unplayable," said the captain.
MANCHESTER CITY VERDICT: Their biggest European win since 1978 had a deceptive scoreline, but was indicative of their ruthlessness at the end. For much of the match, City were on the back foot and this ought to be a pleasing clean sheet. The only disappointments were that the ever-excellent Yaya Toure picked up a booking, ruling him out of the first leg of the last 16 against either Legia Warsaw or Sporting Lisbon, and Barry picked up a knock. He may miss Saturday's game against Blackburn.
PORTO VERDICT: They look a lesser side now that Falcao is no longer around to provide a cutting edge. They were excellent in possession but looked frail at the back. Otamendi, the man responsible for the first goal, got confirmation it was not his day when team-mate Maicon kicked him in the mouth while the less than impressive Hulk was taunted by the City crowd with chants of "you're not incredible".