In the final, against America’s Maya Joint, Sun produced one of her most impressive performances of the week, winning 6-1 6-3.
Sun grew up in Te Anau before moving to Switzerland as a child.
She switched her allegiance back to New Zealand earlier this year after competing under the Swiss flag.
She has, however, retained tight links with Te Anau where her grandparents live, and previously represented New Zealand at junior level.
Sun has won six WTT tournaments previously, one W80 title, a W50, a W25 and three W15 titles, but this victory stands out as the best moment of the 23-year-old’s career.
The WTT is a development tour to feed players into the elite World Tennis Association Tour and on to Grand Slams.
Seeded No 2 for the tournament, Sun went in as one of the favourites and she showed she was able to handle the expectation that goes along with that.
In the final against the 18-year-old Joint, Sun won 83 per cent of the points when she got her first serve in and managed to break her opponent five times.
Sun is anticipated to climb to a career-high world ranking of around 132 by winning in Bonita Springs, which takes her closer to making it onto the direct acceptance lists for grand slams.
After winning the singles at this tournament, Sun was back on court later in the day for the doubles final, where she and her Hungarian partner Fanny Stollar defeated Valentini Grammatikopoulou from Greece and Ukraine’s Valeriya Strakhova 6-4 7-5 to make it a perfect day for Sun.
Sun’s doubles ranking is expected to improve by about 100 spot to take her to around 323 when the rankings are next released.
