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2021 Colorado State Open Tournament Information 

We have reached max tournament capacity, registration for the Colorado State Open is now closed. Please direct any questions to 


USTA Level 4

Tournament Dates:  Friday, Sept 17 - Sunday, Sept 26, 2021

Deadline (whichever occurs first):

  1. Thursday, Sept 9th at 11pm – OR –

  2. A maximum cap in your specific desired Division -OR

  3. A maximum cap of 700 unique participants


Location: Gates Tennis Center, 3300 East Bayaud Ave, Denver, CO

All Tournament Questions:

General: Colorado State Open (CSO) has been running since 1891, making it one of the longest-running state tennis tournaments in the country, and one of the largest. Besides being known as a great tournament, the CSO is also known for offering a great experience for players, vendors, and spectators. The CSO is a special stop on the tournament calendar, attracting players from all around Colorado, and also capturing many players who like to visit Colorado during this special 10-day event.



  • Entries.  All entries via Serve Tennis.  (Click here to register).

  • Lots of choice!  Singles, Doubles, Mixed in nearly every age division and category.

  • Doubles Partner:  When registering for doubles, your partner must be registered prior to your registration in order to select them as your partner. Once you have completed checkout, there is a dropdown menu with all the unpaired players registered for that event. You can select your partner on this page.

  • Family Events– Per a 2019 decision, the CSO Family events have been moved to two weeks after the Colorado State Open; Oct 1-3rd. Registration closes on Sunday, Sept 26th.  Colorado State Open - Family Divisions Click this link!

REFUND POLICY: Participants must be able to play at designated times. ABSOLUTELY NO REFUNDS AFTER THE REGISTRATION DEADLINE.


2021 Modifications:   In taking into consideration a variety of circumstances (COVID, limited staffing, reducing late night matches, etc.), the following modifications have been made to provide a safe and quality tournament.  We apologize in advance for the needed modifications.  Please know, every decision has been painstakingly crafted.  These modifications will allow the Colorado State Open to continue and flourish in 2021 and beyond. We pledge we will do everything possible to put forth an event that will be enjoyable and memorable for all who participate. 


  1. Maximum Size - Players. The event will have a maximum of:   (whichever occurs first)

           a. Cap on number of total entries (700 unique participants)


            b. Cap on draw size (see directly below)

Max Draw Size (based on past CSO draws)

  • All Age Divisions - 16 draw max

  • All Other Divisions - 32 draw max

  • (exceptions, based on historical data, MS 3.5, MS 4.0, MS 4.5, Open MS, Open WS - 64 draw max)


  1. Maximum Size on site/grounds. Cap on number of total players/spectators at GTC at any given time.  This will be based on recommendation by Denver Public Health Department and/or other resources.

  2. Maximum Events.  Max of 2 events per player

  3. Scoring. Use of match play tiebreaker for 3rd set for Age Divisions and NTRP

Prize Money: All Open events: $500 for champion or champion team. $250 for finalist or finalist team.

Match Days and Times:

All Draws are single elimination unless otherwise posted

Draw Posted.   All draws are scheduled to be posted by Wednesday September 15th, 2021 by 4pm.

NTRP Divisions: Begins on Friday Sept 17th.  Potential Match Times will be scheduled: Weekends 7am-9:30pm; and Weekdays 1pm-9:30pm. NTRP concludes Sun. Sept 26.  

AGE Division: Begins on Monday, Sept 20th. Potential Match Times are Weekdays 7am-4pm. AGE concludes Sun. Sept 26.

OPEN Divisions: Scheduled to begin Sunday 9/19; or after depending on the number of participants.  Open Division Finals times of play, will be as follows, excluding inclement weather and are subject to change:

  • WOMENS OPEN SINGLES 9:00am Sunday Sept 26, 2021

  • MEN'S OPEN SINGLES 11:00am Sunday Sept 26, 2021 

  • WOMEN'S OPEN DOUBLES 12pm Sunday Sept 26, 2021

  • MEN'S OPEN DOUBLES  2pm Sunday Sept 26, 2021

  • MIXED OPEN DOUBLES  8:00pm Saturday Night, Saturday Sept 25, 2021

Scheduled match times are final. (All scheduled match times are subject to change per Tournament Committee based on a variety of factors, including weather).

Special Request (before deadline): 

For special requests you must go to – look for the Special Request button.  Unfortunately, due to the size and nature of the Colorado State Open, this is the ONLY method in which to make a Special Request.

  • No guarantee.  CSO tournament staff and volunteers work diligently to TRY to honor requests.  We never guarantee avoidances/conflicts request will be granted. 

  • Cost.  The requests are FREE. 

  • Deadline.  Request must be made before the event is closed; which is when the event is sold out at 700 unique participants -OR- Thursday Sept 9, 2021, whichever comes first. 

  • Please don’t.  No phone, text, personal email, messages left at GTC, etc. requests will be accepted or considered.


HINT #1: If you keep your SPECIAL REQUEST "as narrow as you can", the odds that the request can be successfully honored will increase for you.  IE:  "I can't play Saturday Sept 18th" might have a 33% chance of being a successful request vs. "I can't play Saturday Sept 18th between noon and 5pm" might have a 66% chance of being a successful request.


HINT #2: If your request is too broad “I can’t play matches before 5pm”, (without specifying which day), then this request will not be honored.   If your request is “I can’t play matches before 5pm on Tuesday night”, then your odds rise. 

There are no guarantees with special requests.

SPECIAL REQUESTS: (after deadline)  The Colorado State Open does not consider, under any circumstances, special requests after the Tournament Draw has been posted. 



Thank you for your understanding and support during these difficult times.  We are glad to have you involved with the 2021 Colorado State Open, and we will see you on the courts!  

USTA Changes Tournament Structure