If it's true that the guilty party often can't resist returning to the scene of the crime, then Hulk's pivotal role in Sunday night's scenes at the Estadio da Luz should be little surprise.
Hulk himself would argue that he is no such thing, still burning with a sense of injustice at his punishment following the tunnel brawl following last year's corresponding league fixture between Benfica and Porto. Some 469 days later, the Brazilian exacted the sweetest revenge possible in scoring the goal in the same arena which brought the title back to Porto.
The suggestion that the indefinite suspension placed on Hulk and team-mate Cristian Sapunaru for the incident decided last season's title race crassly overlooks the considerable élan with which Benfica played their way to the title. Nevertheless, the loss of Hulk for 17 games was a bitter blow to the northerners. That Hulk's suspension was commuted to a four-match ban on appeal in March 2010 fuelled Porto's anger at the disciplinary procedure, but Hulk has never allowed himself to be consumed by bitterness. He made a goalscoring return on the other side of Lisbon, against Belenenses at the Estadio do Restelo on March 28, and powered Porto to seven successive wins to finish the season.
That stellar form continued into this campaign, and the first-half penalty at the Luz which turned out to be the title-winning goal was Hulk's 21st in the league alone this season.
"Winning in the home of our closest rival is always something to enjoy a bit more," he said post-match, with considerable understatement. "I already talked about what happened here last year, but thank God I managed to come back well from that."
The excellent Fabio Coentrao handled Hulk much better than the since-departed David Luiz had as a makeshift left-back in November, when Benfica crashed 5-0 at the Dragao in the season's genuinely defining moment. Yet he could not mask the gap between the two sides. Porto played with a confidence that demonstrated their comfort with coming into the match as champions-elect, while Jorge Jesus' side were caught between preserving pride and conserving energy for the more realistic target of the Europa League. Top scorer Oscar Cardozo was left on the bench with Thursday's quarter-final against PSV in mind.
Nevertheless, Benfica and Porto - the club who thrust Portuguese football onto the world stage and the club who have enjoyed their greatest successes in recent years - share a bitter rivalry, and the prospect of Porto's coronation in the home of their rivals further exacerbated matters. The atmosphere outside the Luz was tense before the game, with a heavy police presence visible. Disturbances near the neighbouring Colombo shopping centre saw police firing rubber bullets at troublemakers in an attempt to regain control.
Inside the arena, the 20,000-plus empty seats were reminders of both Benfica's decision to restrict ticket sales to members and of Porto's imminent triumph.
The tension in the playing camps was all on Benfica's side. Porto defender Rolando had said pre-match that even if his side didn't clinch the title at the Luz, they would have the opportunity to do so again the following week at Portimonense. Meanwhile, Coentrao grimly pledged in the build-up: "We have to defend the shirt until the death."
The noise was intense, and the air crackled with malevolence. Inside the first 30 seconds Porto won a corner, but Joao Moutinho twice aborted attempts to take it as debris flew down from the stands. When referee Duarte Gomes pulled play back for a foul on Pablo Aimar with Benfica still in possession but failed to caution the offending Nicolas Otamendi, home crowd and players alike exploded with righteous rage.
Benfica have played some quite wonderful football under Jesus, as the coach has missed no opportunity to point out, but it was clear that Porto had the psychological superiority, retaining their sang froid throughout. The opening goal, in the ninth minute, had betrayed Benfica's nerves. The in-form Guarin would claim the goal as a record-breaking fifth in five games, but that his intended cross found the net owed everything to the fumbling of Roberto. It starkly recalled the generally excellent Spanish goalkeeper's error-strewn start to the campaign that put the skids under Benfica's title defence early on.
Jesus' counterpart André Villas Boas is usually demonstrative but reacted with circumspection, preferring a quiet word with his goalkeeper and captain Helton to joining the celebrations. A frustrated Jesus meanwhile flapped furiously on the edge of his technical area like a misanthropic eagle. The cliché of coaches living every kick never seemed so apt, with both coaches pacing, protesting and gesticulating on the very edge of the playing area.
Villas Boas later added another milestone to his record-breaking season, at 33 becoming the youngest coach to win the Portuguese league, in his debut season at the helm of his hometown club. Last year the perpetually unchallenged Porto had been blown away by the intensity, as well as the aesthetic fluency, of Benfica's football. Instilling a high-pressing, energetic philosophy into his new side, Villas Boas ensured that Porto wouldn't be caught out in the same way this term.
"It was the first time in many years that Benfica got the title instead of us last year," midfielder Fernando Belluschi told ESPNsoccernet after the game. "The whole group deserves this. We worked so hard this year. For me, it's the best moment of my career. I won the title in Argentina but winning the title here, against the team that is always our rival, has a different taste."
As the final whistle went and Porto's championship was confirmed, their players erupted with joy, scampering across the field jumping and fist pumping. Then the lights went out and the sprinklers went on, with the hosts keen to draw the curtains on their rivals' celebrations, but Porto's players continued frolicking in the dark. They showered under the jets of water in the manner of Real Madrid in the Cibeles fountain, as Eurohouse versions of Benfica songs pumped out over the PA. It summed up Porto's season, with Villas Boas' inventiveness handing his club new life.