BUENOS AIRES, Nov 1 (Reuters) - Titleholders River Plate slumped to a 2-0 defeat at Lanus on Saturday, extending their winless domestic run to an unprecedented 11 games.
The defeat guaranteed beleaguered coach Diego Simeone's team, who have nine points from their 13 games, would finish the weekend bottom of the Apertura championship.
Simeone made nine changes from the team that drew 1-1 with Newell's Old Boys on Wednesday but saw his side fall behind after only five minutes to a goal from Diego Lagos.
Maximiliano Velasquez added a second early in the second half to lift Lanus to fourth in the table.
River's next match is a Copa Sudamericana quarter-final second leg tie away to Mexican side Guadalajara on Thursday and Simeone is expected to face the sack if his side fail to overturn their 1-0 deficit.
The only consolation for River, one of Argentina's biggest clubs, is that they are in no danger of relegation, which is decided over three seasons.
Second-placed Tigre's title hopes took a knock when they lost 2-0 to struggling Argentinos Juniors, who scored both their goals in a three-minute spell in the first half.
Carlos Recalde put Argentinos ahead with a 30-metre free kick in the 34th minute and Ignacio Canuto turned the ball in from close range following another set piece.
Tigre have 26 points from 13 games and trail leaders San Lorenzo on goal difference. San Lorenzo visit Boca Juniors, who have 23 points, on Sunday.
Huracan celebrated the club's 100th birthday by beating Estudiantes 1-0 despite being reduced to 10 men when Ariel Colzera was sent off for a bad challenge on Leandro Desabato in the 63rd minute.
Huracan kept pressing and were rewarded when midfielder Gaston Esmerado rifled in a 20-metre left-foot shot with three minutes to play.