Doubles runner-up in 2003 and 2004, Janko Tipsarević won the singles in 2006
The MT:S Open powered by Sony Ericsson (known until 2009 as the GEMAX Open) and known as the Belgrade Challenger was a professional tennis tournament played on outdoor clay courts. It was part of the ATP Challenger Tour and the Challenger series of the WTA Tour. It was also part of the Tretorn SERIE+ of the Challenger Tour.[1] It was held annually at the Tennis Club Gemax until 2010 before its relocation to the Novak Tennis Centre since 2021 in Belgrade, Serbia. The tournament was first played in 2002. A one-year women's edition was held in 2021.