2021 San Diego Open

DateSeptember 27–October 3

Edition35th (1st as ATP 250 event)

CategoryATP Tour 250

Draw28S / 16D

2021 San Diego Open
Date	September 27–October 3
Edition	35th (1st as ATP 250 event)
Category	ATP Tour 250
Draw	28S / 16D
Prize money	$600,000
Surface	Hard / outdoor
Location	San Diego, United States
Venue	Barnes Tennis Center
Champions
Singles
Casper Ruud
Doubles
Joe Salisbury / Neal Skupski
← 2015 · San Diego Open · 2022 →

The 2021 San Diego Open was a men's tennis tournament played on outdoor hard courts. It was the 1st edition of the San Diego Open, and part of the ATP Tour 250 series of the 2021 ATP Tour. It was held at the Barnes Tennis Center in San Diego, United States, from September 27 until October 3, 2021. It was primarily organized due to the cancellation of Asian tournaments during the 2021 season, because of the ongoing COVID-19 pandemic.

Positioned one week before the 1000 Indian Wells Masters and only a 2-hour 30 min drive from Indian Wells, the San Diego Open attracted a very strong line up of players including Denis Shapovalov, Andrey Rublev, Grigor Dimitrov and Andy Murray.^[1] With 8 of the top 20 players attending and the ranking cut off being 42 to get into the main draw it was the second most competitive ATP 250 all season since Doha.

Daniel Vallverdu took on the position of managing director,^[2] Ryan Redondo^[3] was named the tournament director and Billie Jean King^[4] accepted the role of honorary tournament chair.