2018

Rai's first experience of professional tennis was being given a wildcard into qualifying for the Auckland Open, where he was beaten by Taro Daniel in the first round. He played his first senior ITF tournament in Kampala, Uganda, in May, qualifying for the main draw in singles, where he reached the second round. The following week, at the same venue, he was given a wildcard into both doubles and the main draw for singles, and reached the quarterfinals of both.

He reached his first doubles semifinal in China in July, but the highlight of his year to that date would come in September, when he made his Davis Cup debut for New Zealand, partnering Artem Sitak to win their doubles rubber against South Korea, giving Rai a perfect start to his senior international representative career. His first ITF doubles final came in Hua Hin, Thailand, in October, where he and Karunuday Singh lost in a match tie-break to the top seeds, Francis Casey Alcantara and Sonchat Ratiwatana. In singles at the same tournament, he progressed past the quarterfinals for the first time, going all the way to take the title over Manish Sureshkumar in three sets. His season finished with a couple of quarterfinal losses in Futures events in Tây Ninh, Vietnam.

2019

Again given a wildcard into qualifying in Auckland, Rai was a game away from defeating Roberto Marcora in the first round before eventually losing in three sets. He and New Zealand junior champion George Stoupe were given a wild card into the doubles, where they lost in the first round to Artem Sitak and Austin Krajicek.

In Uganda on the anniversary of his ITF debut, Rai injured his back severely enough in his second event to need three months' rehabilitation before he returned to the tour in South-East Asia. Well-beaten in his first match, he steadily improved through a series of tournaments to reach another doubles final in Hua Hin in August. By the worst possible luck, his partner, former dual Australian Open junior doubles winner Bradley Mousley, injured his knee in his singles semifinal earlier in the day and had to retire from that match. He played the doubles final, but with very restricted movement the pair were easily beaten by the top-seeded Ratiwatana twins from the host country.

Rai reached two more ITF doubles finals before the end of the year, in Hua Hin two weeks later and in Cancún, Mexico, in late November, finishing runner-up on each occasion.

2020

With the ITF Circuit returning to New Zealand for the first time in several years, Rai's first event for 2020 was at the new tournament in Te Anau, where he lost in the quarter-finals of both singles and doubles. At the ASB Classic in Auckland, Rai received a wildcard into both the singles qualifying rounds and the doubles, losing his first match in both. The doubles defeat, however, came at the hands of the eventual champions, Luke Bambridge and Ben McLachlan, and Rai and partner Mackenzie McDonald played extremely well.

Rai's next stop after Auckland was Cancún, where he played three tournaments in as many weeks. The second was the most productive, reaching the quarterfinals in singles and finally securing a doubles title, in his fifth final. Rai then returned home for New Zealand's Davis Cup tie against Venezuela in Auckland, where he lost in singles to Luis David Martínez in three sets. He didn't play again before the international tour was suspended due to the COVID-19 pandemic, and his only subsequent events were domestic tournaments such as the New Zealand Premier League, Wellington Open/New Zealand Championships (where he finished runner-up) and the Te Anau Invitational.

2021

Rai resumed his international career in June, playing a series of ITF tournaments in Monastir over the next couple of months. He reached several doubles finals but, frustratingly, it took five attempts before he was able to win another title. Apart from a brief trip to Spain to renew his visa, he stayed in Monastir until November, eventually winning six doubles titles from 11 finals before returning to New Zealand.

2022

2022 had to be considered a successful year for Rai, as he made three more ITF singles finals, winning the last of them at the first of two new tournaments in his home country. He also took the doubles title at Nonthaburi in his very first ATP Challenger event.

Singles: 5 (3 titles, 2 runners-up)

Result	No.	Date	Level	Tournament	Surface	Opponent	Score
Win	1.	13 October 2018	15,000	Hua Hin, Thailand	Hard	Manish Sureshkumar	6–3, 4–6, 6–4
Loss	1.	28 August 2022	M15	Changwon, Korea Rep.	Hard	Lee Jea-moon	4–6, 4–6
Loss	2.	9 October 2022	M25	Tây Ninh, Vietnam	Hard	Lý Hoàng Nam	4–6, 4–6
Win	2.	18 December 2022	M15	Wellington, New Zealand	Hard (i) [Note 1]	James Watt	6–2, 6–4
Win	3.	8 October 2023	M25	Cairns, Australia	Hard	Jeremy Beale	3–2, ret.

Note 1: this was an outdoor tournament, but several matches, including the final, were played indoors due to bad weather.

Doubles: 22 (11 titles, 10 runners-up, 1 pending)

Result	No.	Date	Level	Tournament	Surface	Partner	Opponents	Score
Loss	1.	12 October 2018	15,000	Hua Hin, Thailand	Hard	Karunuday Singh	Francis Casey Alcantara Sonchat Ratiwatana	1–6, 6–1, [6–10]
Loss	2.	24 August 2019	M15	Hua Hin, Thailand	Hard	Bradley Mousley	Sanchai Ratiwatana Sonchat Ratiwatana	2–6, 0–6
Loss	3.	7 September 2019	M15	Hua Hin, Thailand	Hard	George Loffhagen	Ray Ho Kelsey Stevenson	6–7(4–7), 2–6
Loss	4.	23 November 2019	M15	Cancún, Mexico	Hard	Cameron Green	Skyler Butts Nicholas Bybel	5–7, 5–7
Win	1.	1 February 2020	M15	Cancún, Mexico	Hard	Simon Carr	Gabriel Petit Brandon Walkin	6–4, 6–2
Loss	5.	29 May 2021	M15	Monastir, Tunisia	Hard	Siddhant Banthia	Jeremy Beale Thomas Fancutt	4–6, 4–6
Loss	6.	12 June 2021	M15	Monastir, Tunisia	Hard	Jeremy Beale	Siddhant Banthia Park Ui-sung	w/o
Loss	7.	26 June 2021	M15	Monastir, Tunisia	Hard	Benjamin Winter Lopez	Julian Cash Mark Whitehouse	6–7(1–7), 3–6
Loss	8.	17 July 2021	M15	Monastir, Tunisia	Hard	Jeremy Beale	Arthur Bouquier Santiago Rodríguez Taverna	7–5, 4–6, [7–10]
Win	2.	7 August 2021	M15	Monastir, Tunisia	Hard	Blake Ellis	Taisei Ichikawa Seita Watanabe	6–2, 6–3
Win	3.	11 September 2021	M15	Monastir, Tunisia	Hard	Mattia Bellucci	Gabriel Décamps Robert Strombachs	7–6(7–1), 6–7(5–7), [10–4]
Win	4.	18 September 2021	M15	Monastir, Tunisia	Hard	Li Tu	Martin Breysach Lilian Marmousez	6–0, 6–4
Loss	9.	25 September 2021	M15	Monastir, Tunisia	Hard	Giorgio Ricca	Guy Orly Iradukunda Marat Sharipov	3–6, 6–4, [6–10]
Win	5.	16 October 2021	M15	Monastir, Tunisia	Hard	Mateo Nicolás Martínez	Anis Ghorbel Mirko Martinez	6–7(1–7), 6–4, [11–9]
Win	6.	30 October 2021	M15	Monastir, Tunisia	Hard	Mirko Martinez	Théo Arribagé Axel Garcian	6–4, 1–6, [10–8]
Win	7.	6 November 2021	M15	Monastir, Tunisia	Hard	Mirko Martinez	Pierre-Yves Bailly Martin Katz	3–6, 7–6(7–5), [10–8]
Win	8.	27 August 2022	M15	Changwon, Korea Rep.	Hard	Thomas Fancutt	Jeong Yeong-seok Lee Jea-moon	5–7, 6–4, [10–8]
Win	9.	10 September 2022	Challenger	Nonthaburi, Thailand	Hard	Chung Yun-seong	Francis Casey Alcantara Christopher Rungkat	6–1, 7–6(8–6)
Loss	10.	5 November 2022	Challenger	Sydney, Australia	Hard	Yuta Shimizu	Blake Ellis Tristan Schoolkate	6–4, 5–7, [9–11]
Win	10.	23 September 2023	M25	Darwin, Australia	Hard	Thomas Fancutt	Blake Bayldon Brandon Walkin	6–1, 6–4
Win	11.	25 November 2023	M25	Brisbane, Australia	Hard	Thomas Fancutt	Joshua Charlton Emile Hudd	6–4, 6–4
Pending	12./11.	3 December 2023	M25	Carrara, Australia	Hard	Thomas Fancutt	Blake Bayldon Kody Pearson