Mario Lepe's Catolica grabbed a potential crucial away goal ahead of the second leg on August 16, with Pablo Calandria heading home from Felipe Gutierrez's free-kick shortly before half-time.
The goal levelled the game after Ignacio Nicolini had put Bella Vista ahead from the penalty spot in the 24th minute.
Bella Vista midfielder Marcelo Martuciello admitted his team had struggled for fitness after a shortened pre-season.
"Our preparations were short because we had planned for the season to start in two weeks and then the Copa Sudamericana was rescheduled," he told Fox Sports.
"We improved in the second half. It is a good result for us but we promise to do a better job in the second leg."
In Peru, Universidad Cesar Vallejo drew 1-1 with Santa Fe of Colombia.
Mario Leguizamon opened the scoring with a free kick in the third minute before Oscar Rodas levelled six minutes into the second half.
The second leg will be played on August 23rd in Bogota.