BUENOS AIRES: Boca Juniors' 'Superclasico' clash with River Plate, the biggest game of the Argentine season and among the most passionate in world soccer, finds the rivals out of the title race in a controversial 30-team championship. Bragging rights at La Bombonera on Sunday will therefore be limited to the teams' Copa Libertadores performances and the form of two fan favourites back from successful overseas careers  Boca's Carlos Tevez and Andres D'Alessandro of River. Tevez, who came home last June after successful spells in Manchester with Premier League United and City plus a stint at Juventus, helped Boca win the first division title in November, earning them a place in this year's Copa Libertadores. D'Alessandro, 35, returned to Libertadores holders River in January having spent the last seven years with Internacional in Brazil and was at his playmaking best in a 6-0 home rout of Bolivia's The Strongest two weeks ago. Ahead of the 'Superclasico', Boca host Colombia's Deportivo Cali in their last Libertadores group match on Wednesday with their second-roun place already in the bag, while River welcome Venezuela's Trujillanos on Thursday needing a draw to be sure. The league championship is called 'Transicion', bridging the gap between the 2015 calendar-year tournament and a return to a season aligned with Europe's soccer calendar starting in August. It retains the 30 clubs introduced last year but divides them into two groups of 15 so each team faces 14 sides in the four-month championship once, home or away, and their local derby rivals twice, home and away, with the group winners meeting in the May 29 final. Added to the controversial format inherited from the late Argentine FA leader Julio Grondona, who died in July 2014, is the decision to give the top three teams in this short championship places in next year's Copa Libertadores. This has put the onus on the likes of Boca and River to win the continental crown this year to be sure they are in it again in 2017 as they have fallen too far behind in the domestic standings to qualify via their league position. Boca, 11 points off the pace in fifth spot in their group, go into the match after a 4-1 home win over modest Aldosivi, while River, eight points adrift in ninth in their group, won 1-0 at Olimpo at the weekend to end a five-match winless run. Although River dominated February's 'Superclasico' at El Monumental, Boca managed to escape with a 0-0 draw.