Serbia Challenger Open

MT:S Open powered by Sony Ericsson
2021 Belgrade Challenger
Defunct tennis tournament
Event nameBelgrade Challenger
Founded2002
Abolished2021
LocationBelgrade, Serbia
VenueNovak Tennis Center
(formerly: SRPC Milan Gale Muškatirović)
SurfaceClay / Outdoors
WebsiteSerbia Open
Current champions (2021)
Men's singles Roberto Carballés Baena
Women's singles Anna Karolína Schmiedlová
Men's doubles Guillermo Durán
Andrés Molteni
Women's doubles Olga Govortsova
Lidziya Marozava
ATP Tour
CategoryChallenger 125
Draw32S / 16Q / 16D
Prize money€132,280 (2021)
WTA Tour
CategoryWTA 125
Draw32S / 8Q / 11D
Prize moneyUS$115,000 (2021)

The MT:S Open powered by Sony Ericsson (previously the GEMAX Open) and also 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. It was held annually at the Tennis Club Gemax until 2010 before its relocation to the Novak Tennis Centre in 2021 in Belgrade, Serbia. The tournament was first played in 2002. A one-year women's edition was held in 2021.