At the 1998 World Aquatics Championships in Perth, Australia, Borges finished fifth in the 100-meter freestyle, eighth in the 200-meter freestyle and sixth in the 4×100-meter freestyle. At the end of 1998, Borges was part of the Brazilian team which broke its third consecutive world record in the 4×100-metre freestyle relay on short course. On December 20, shortly after the end of the Jose Finkel Trophy, Fernando Scherer, Carlos Jayme, Alexandre Massura and Gustavo Borges, in order, fell the pool at Club de Regatas Vasco da Gama with a time of 3:10.45, which would only be broken in 2000 by the Swedish team. At the same tournament, Borges also broke the South American record in the 100-meter freestyle in short course with a time of 47.14 seconds and the 200-meter freestyle record with a time of 1:44.40the last record-breaking swims of his career.