Boca Juniors earned their 23rd Argentine title by winning a three-team playoff on goal differential despite a 1-0 loss to Tigre on Tuesday.
Tigre's Leandro Lazzaro scored in the 67th minute, heading in Matias Gimenez's cross in front of Boca goalkeeper Javier Garcia.
"We deserved to be champions," Boca defender Claudio Morel Rodriguez said. "Tigre was a great opponent, but we managed the game and they almost didn't create any danger."
Boca, Tigre and San Lorenzo ended the Apertura tied with 39 points, setting up the second ever three-way round-robin to decide the league winner.
Boca claimed the title with the only positive goal difference. San Lorenzo beat Tigre 2-1 last Wednesday, then Boca beat San Lorenzo 3-1 on Saturday.
The blue and gold could afford to lose 1-0 at neutral Racing Stadium on Tuesday, while Tigre could have won its first national title with a two-goal win. A title for Tigre would have defied the odds. Boca's star midfielder Juan Roman Riquelme cost more to sign - $15 million (11 million euros) - than Tigre's entire roster.
"Tigre also deserved the title, they had a great championship," Boca coach Carlos Ischia said.
Boca won its first domestic title since the 2006 Clausura. It last won the Apertura in 2005.
Boca played without injured star forward Martin Palermo or Riquelme, who was suspended for the match after accumulating five yellow cards.
And forward Rodrigo Palacio was expelled in stoppage time when he received two quick yellow cards for delay of game and protesting too vehemently.
Ischia pulled Garcia shortly after he conceded the goal, in a rare 'keeper substitution. It was not immediately apparent that Garcia was injured.
"Cry, cry, cry River, cry," Boca's fans sang as the seconds ticked down on an Apertura season made perhaps as memorable by bitter rival River Plate's last-place finish.
It was the second time the Apertura has been extended to a three-team playoff. In 1968, Velez Sarsfield won the round-robin against River Plate and Racing Club.
(Agencies via China Daily December 25, 2008)
