BUENOS AIRES - Boca Juniors beat nine-man San Lorenzo 3-1 in the second game of the three-way Argentine championship playoff on Saturday to set up a title decider against Tigre on Tuesday. Playmaker Juan Roman Riquelme set up two of Boca's goals but also earned a fifth yellow card which will rule him out of Tuesday's match. Lucas Viatri, Rodrigo Palacio and Cristian Chavez scored for Boca on a scorching afternoon at neutral Racing Club while Santiago Solari replied for San Lorenzo, who beat Tigre 2-1 in the mini league's opening match but are now out of the running. San Lorenzo had Gaston Aguirre and Gonzalo Bergessio sent off and six other players booked while Boca had five players shown the yellow card. Boca, San Lorenzo and Tigre finished level on points at the top of the regular tournament, sending the title race to a three-way playoff as goal difference is not used. Saturday's result left Boca and San Lorenzo with three points each in the mini-league and Tigre with none. Goal difference will be used to settle the mini-league if the teams finish level on points, followed by the head-to-head record of the teams during the regular championship. This gives Tigre the upper hand as they beat both the other pair while Boca beat San Lorenzo. UGLY CLASH Play was held up for five minutes during the first half after an ugly clash of heads involving Boca defender Juan Forlin and San Lorenzo striker Andres Silvera, who were both taken to hospital for treatment. Media reports said their condition was not serious. Viatri put Boca ahead in first-half stoppage time when he headed in Riquelme's perfectly floated corner at the near post. Former Real Madrid striker Solari levelled out of the blue in the 61st minute when his soft shot slipped through the hands of Boca goalkeeper Javier Garcia. Boca regained the lead in the 77th minute when Garcia's long kick out of defence found Jesus Datola on the left. Datola's crossfield pass found Riquelme who laid off a neat ball into the middle for Palacio to fire home. San Lorenzo lost their heads as Aguirre and Bergessio were both dismissed for second bookable offences in the last 10 minutes, Bergessio leaving the field in a fit of rage. Substitute Chavez added the third when he cut inside his marker and scored with a low shot from 20 metres.