Gremio fire Roth after derby day defeat
Roth was dismissed after his team lost to arch-rivals Internacional 2-1 on Sunday, their fourth successive defeat against their neighbours, and only a day before a Libertadores Cup match at home to Aurora.
He was the seventh coaching victim at Brazil's 20 first division clubs since the season started in late January.
The club said on its website that Marcelo Rospide would take charge on a caretaker basis for Tuesday's Group Seven match against the Bolivian side.
Roth, who previously coached Gremio in 1998 and 2000, was dismissed even though Gremio are top of their group in the Libertadores, which is their priority for the season, with seven points from three games.
Sunday's defeat came in the Gaucho championship, a regional tournament which is a prelude to the Brazilian season.
The 51-year-old, who had been in charge for just over one year, has coached at 14 other Brazilian clubs and worked in Qatar and the United Arab Emirates.