Having scored six goals in two matches, Fenix are top – and their latest victory was a 4-1 thrashing of Sud America.
Nacional are also two from two after Ivan Alonso's brace led them to a second straight 2-0 win, this time over Rentistas.
At the Estadio Parque Capurro in Montevideo, Anibal Hernandez struck a brace in the opening half-hour for Fenix.
The match was all but over at the break as Lucas Cavallini made it 3-0 four minutes before the interval.
Santiago Carrera netted a consolation goal for the visitors before Martin Liguera struck to complete Fenix's win.
At Nacional, Alonso converted a fifth-minute penalty and completed his brace just after the hour-mark in his team's victory.
Liverpool and Wanderers are third and fourth respectively after the latter came from behind to earn a 2-2 draw.
Penarol and Defensor Sporting played out an entertaining 2-2 dra, while Cerro Largo and River Plate did likewise.
Juventud are alongside Rentistas in being without a point this season after being hammered 4-0 by El Tanque Sisley.
Junior Arias scored a brace for El Tanque Sisley, who jumped up to sixth on the table with their first win.
Danubio drew their second straight game in a 1-1 result at Cerro and Racing scored twice late on to beat Miramar Misiones 2-0.
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