It's Singles Day at the Proton Tucson Open, with action taking place at Tucson Tennis and Racket Club.

Broadcast coverage is available on Pickleballtv at 1pm ET.

You can also stream courts on the Pickleballtv app, which is available for download in the Apple and Android app stores.

Click here to see the draws for each event.

Stay tuned for live updates throughout the day.

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4:40pm CT: Duong's retirement sends H. Johnson into semis

Hunter Johnson is into the men's singles semifinals after Quang Duong was forced to retire from their quarterfinal bout with a groin injury.

Despite the injury, Duong expects to be able to play mixed doubles on Friday with Alix Truong.

As for the singles, Johnson will now face No. 7 seed Dylan Frazier for a spot in the finals.

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4:10pm CT: Women's Singles quarterifnals

Here are the four women's singles quarterfinal matchups:

• No. 1 seed Kaitlyn Christian v. No. 6 seed Mary Brascia
• No. 4 seed Kate Fahey v. No. 8 seed Dominique Schaefer
• No. 2 seed Lea Jansen v. No. 5 seed Parris Todd
• No. 3 seed Brooke Buckner v. No. 7 seed Zoey Wang
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3:45pm CT: Alshon, Sock use dominant performances to set semifinal clash

Christian Alshon and Jack Sock became the first two players to advance to the men's singles semifinals in Tucson, and they both did so in dominant fashion.

Alshon advanced by way of an 11-3, 11-0 victory over No. 15 seed Eric Roddy. After the No. 6 seed got up 4-3 in the opening game, he didn't give up another point on the scoreboard as he got one step closer towards to earning his first singles medal since last May.

Sock was just as impressive, coming away with an 11-7, 11-5 victory over PPA Masters silver-medalist Jaume Martinez Vich. As he's known to do, Sock ripped forehand winners from seemingly everywhere on the court in his cleanest match of the day so far.

Alshon and Sock will face off for a spot in Sunday's final.

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3:20pm CT: Men's singles quarterifinals

Here are the four men's singles quarterfinal matchups:

• No. 15 seed Eric Roddy v. No. 6 seed Christian Alshon
• No. 4 seed Jaume Martinez Vich v. No. 8 seed Jack Sock
• No. 2 seed Connor Garnett v. No. 7 seed Dylan Frazier
• No. 3 seed Hunter Johnson v. No. 5 seed Quang Duong
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3:10pm CT: Duong saves four match points, outduels Ford in three games

Quang Duong claimed the final quarterfinal spot in the men's singles draw with a tightly contested 8-11, 14-12, 11-4 victory over No. 21 seed Zane Ford.

Truthfully, it was a contest that Duong had no business winning. At separate points in the second game, he trailed 0-5 and 5-10 before saving four match points to bring on the decider.

The 18-year-old carried that momentum with him into Game 3 and comfortably triumphed from there.

He will face No. 3 seed Hunter Johnson in the quarterfinals.

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2:20pm CT: Roddy ends Evans' run, surges into quarterfinals

Tom Evans may have scored the win of the day in the men's singles draw, but it's Eric Roddy who is moving on after the two faced off in the Round of 16.

The No. 15 seed used a strong Game 3 performance to earn an 11-8, 7-11, 11-2 triumph over the No. 37 seed and advance to the quarterfinals.

Roddy will next face No. 6 seed Christian Alshon as he looks to make it to a singles semifinal on the PPA Tour for the second time in his career.

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2:00pm CT: Late run helps Imparato defeat Parker

Pierina Imparato is into the women's doubles Round of 16 after a 7-11, 13-11, 12-10 victory over No. 12 seed Samantha Parker.

It looked like the match was getting away from Imparato when she trailed 1-4 in the third game, but she went on to score the next seven points and was eventually able to close out the back-and-forth encounter.

She will face No. 8 seed Dominique Schaefer in the Round of 16.

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12:55pm CT: Evans upsets Staksrud in three games

Tom Evans pulled off what could go down as the upet of the tournament with an 11-2, 5-11, 11-8 victory over top-seeded Federico Staksrud in the Round of 32. 

Read the whole article about the match here.

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11:50am CT: Women's Singles Qualifiers

Here are the four players who are advancing to the women's singles main draw after battling through qualifying early Thursday morning, and who they'll play in the first round.

• Jalina Ingram: will play No. 7 seed Chao Yi (Zoey) Wang.
• Sahra Dennehy: will play No. 3 seed Brooke Buckner.
• Bryanna Ojeda: will play No. 8 seed Dominique Schaefer.
• Cailyn Campbell: will play No. 4 seed Kate Fahey.
• Alli Hazrati: will play No. 1 seed Kaitlyn Christian.
• Hsiang wen Huang: will play No. 2 seed Lea Jansen.
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11:40am CT: Evans off to winning start on American soil

In his first match in America since signing a UPA contract, Tom Evans defeated No. 29 seed Ryan Fu 11-8, 11-7 to begin his campaign in Tucson.

The Australian star’s most notable result in the U.S. came at the Orange County Cup last June, where he beat Rafa Hewett and Tyler Loong to make the Round of 16 before falling to Federico Staksrud.

Coincidentally, he'll next face Staksrud in the Round of 32. 

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Men's Singles Qualifiers

Here are the eight players who fought through the men's singles qualifying rounds on Wednesday and who they'll play in the first round: 

• Spartak Rahachou: will play No. 25 seed Blaine Hovenier.
• Mouaad Alhouni: will play No. 21 seed Zane Ford.
• Thomas Yu: will play No. 24 seed Ryan Sherry.
• Anouar Braham: will play No. 23 seed Julian Arnold.
• Rio Newcombe: will play No. 30 seed Augie Ge.
• Yuta Funemizu: will play No. 22 seed Mohaned Alhouni.
• Carl Hilliard: will play No. 19 seed Marshall Brown.
• Sebastian Herrera: will play No. 18 seed Cason Campbell.
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