2021 Open de Oeiras IV

The 2021 Open de Oeiras IV was a professional tennis tournament played on clay courts. It was the fourth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Oeiras, Portugal between 24 and 30 May 2021.

2021 Open de Oeiras IV
Date	24–30 May
Edition	4th
Surface	Clay
Location	Oeiras, Portugal
Champions
Singles
Gastão Elias
Doubles
Jesper de Jong / Tim van Rijthoven

Singles main-draw entrants

Seeds

Country	Player	Rank1	Seed
FRA	Mathias Bourgue	195	1
TPE	Wu Tung-lin	267	2
GER	Julian Lenz	269	3
TPE	Tseng Chun-hsin	274	4
ECU	Roberto Quiroz	275	5
ESP	Carlos Gimeno Valero	286	6
ARG	Pedro Cachin	292	7
ITA	Riccardo Bonadio	293	8

• ¹ Rankings are as of 17 May 2021.

Other entrants

The following players received wildcards into the singles main draw:

• Pedro Araújo
• Tiago Cação
• Luís Faria

The following player received entry into the singles main draw using a protected ranking:

• Viktor Galović

The following player received entry into the singles main draw as an alternate:

• Corentin Denolly

The following players received entry from the qualifying draw:

• Filip Cristian Jianu
• Nikolás Sánchez Izquierdo
• Timofey Skatov
• Denis Yevseyev

Champions

Singles

Main article: 2021 Open de Oeiras IV – Singles

• Gastão Elias def. Holger Rune 5–7, 6–4, 6–4.

Doubles

Main article: 2021 Open de Oeiras IV – Doubles

• Jesper de Jong / Tim van Rijthoven def. Julian Lenz / Roberto Quiroz 6–1, 7–6^(7–3).