Starting as the overnight third-round leader, Rhodes built on her experience from three Curtis Cup appearances for Great Britain to secure the Jan Stephenson Trophy with a bogey-free final-round two-under-par 69.
Rhodes finished the tournament at 17 under after converting a three-shot lead heading into the back nine on Sunday with 14 consecutive pars from the fifth hole.
Australian Kirsten Rudgeley tied for second with Italian Alessandra Fanali after closing with a 68.
Fanali, coming off a career-best round of 64, closed within one shot after a birdie on the 17th but finished tied at 15 under with Rudgeley after posting a Sunday round of 70.Â
Spanish star Nuria Iturrioz, a four-time LET winner, had an early surge with three birdies in the first five holes but paid for her aggressive style with a bogey on the seventh and a double bogey on No.9 that all but ended her challenge.
"I'm still in shock, but I'm so happy," Rhodes said.
"I've worked really hard. I didn't have a great week last week, so I wasn't really expecting much.
"But I went through a bit of a swing change, and it obviously worked this week. So yeah, I'm just really happy."
Asked about her nerves coming down the stretch, the 24-year-old said, "I was fine for the front nine, but when it started to get tight, I got a bit stressed.
"I was asking my caddy how the group in front was doing and how many shots ahead I was.
"But I just kept breathing, stayed focused, and tried not to think ahead. It's difficult in those situations, but yeah, I'm just really glad I got it done."
Rhodes credited her putting as a key factor in her performance.
"From the second round, my putting was really good. I placed the ball really nicely on the green," she said.
"I didn't even realise I hadn't made a bogey in the last two rounds. I was just trying to stay calm and focused out there. I wasn't putting too much extra attention on myself after the second round."
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