BUENOS AIRES - Playmaker Juan Roman Riquelme scored twice to give Boca Juniors a 2-1 win over Racing Club and keep them top of the Argentine championship on Sunday. Unfashionable Tigre moved into second place after coming from behind for a 3-1 win over defending champions River Plate who, incredibly, are bottom of the table. San Lorenzo, previously second, dropped to fourth after their game against Huracan on Saturday was suspended by a torrential downpour in the 16th minute. The Argentina Football Association has not yet announced when the match, which Huracan were winning 1-0, will be completed. With two games to play, Boca lead the Apertura championship with 35 points from 17 games, two ahead of Tigre. Riquelme opened the scoring with a 40th-minute penalty, ignoring provocation from goalkeeper Pablo Migliori to place the ball calmly in the bottom left corner. The penalty was controversially awarded for a foul by Migliori on Luciano Figueroa. Franco Sosa outjumped a group of Boca defenders to head Racing level in first-half stoppage time. After becoming involved in an altercation with a supporter in the members' seats who apparently insulted him early in the second half, Riquelme volleyed the winner on the hour. He then ran 50 metres to celebrate in front of the fan who became involved in a fight with other supporters around him. Tigre fell behind when Paraguay striker Santiago Salcedo curled in a second-minute free kick for River before two goals from Carlos Luna gave them a 2-1 halftime lead. Luna got in behind the River defence to equalise in the 26th minute and latched on to Martin Morel's incisive pass to chip the second in first-half stoppage time. River dominated the second half but Tigre held on and added the third in the fifth minute of stoppage-time when Morel sent Cristian Bardaro clear and he chipped over goalkeeper Daniel Vega. Bardaro, who had only been on the pitch for a few minutes, was sent off as he picked up a second yellow card for a shirtless goal celebration.