The unbeaten Vietnamese boxer beat Thailand's Kitidech Hirunsuk after 12 rounds to take the vacant 48kg category belt at Saigon Sports Club on March 20.
He then advanced into the world's top 10 boxers in the WBA on April 1.
Toan returned to the same venue on October 1, and he only needed three rounds to better Indonesian veteran Silem Serang at the 'LEAD: The Beginning' event.
In 2020, Toan fought in Manila in his third professional fight in February, and he stopped host Benjie Bartolome in two rounds.
The 29-year-old is currently ranked ninth in the world and is unbeaten in five fights, with three knockouts.
"I myself find this will be a difficult task. Amparo is a tough and professional boxer who can withstand high pressure," Toan told Việt Nam News.
"But in this bout, I believe in making it a spectacular match to the audience at the event, as well as my supporters at home."
As well as training hard for his title defence, he manages a school construction project online in Dien Bien Province.
"Physically, I follow a strict training and nutritional plan daily. My coaching board and I focus on training and mapping out suitable tactics. Everything is to make sure I am at my best for the match.
"I am confident and will bring home another victory," he said.
He said he is much better than eight months ago when he won the title.
"I am more experienced with lessons collected from local and international matches. My style is also more flexible and diverse. As a result, my fitness is better, and I can keep up the pressure until the end of the 12th round."
Toan in May held a tour by bike from HCM City to Hanoi in 14 days to call for donations to build a school in the mountainous Yen Village, Muong Toong Commune, Muong Nhe District.
He has collected more than VND400 million (US$16,000), and the school is on the way to being completed. The project covers two classrooms, a kitchen, a toilet, a playing ground with a fence and a 60m road leading to the school campus.
Currently, he is planning another project for children in the northern province of Ha Giang, which is expected in the coming years.
For his opponent, the WBA Asia minimumweight championship will be the biggest fight in the Boholano boxer Amparo's career.
The 25-year-old, who has a record of 11 wins (two KOs), one draw and three losses (2KOs), is one of the most active Filipino boxers. This will be his fight in less than four months and his sixth this year.
He went to South Africa on October 23, beating the previously unbeaten boxer Mthokozisi Ngxaka by unanimous decision. Before that, he also defeated the tough Ariston Aton on September 9 in Dimiao, Bohol.
Amparo, a native of Guindulman town, is currently on a five-fight winning streak. His last setback was on September 27, 2021, when he lost to fellow countryman Regie Suganob via unanimous decision.
Both Amparo and Suganob are now training under the PMI Bohol Boxing Stable in Tagbilaran City, Bohol.
Amparo, the Filipino No 1, is also the reigning WBF-Asia Pacific minimumweight champion.
According to BoxRec, Amparo is placed No 21, 14 steps higher Toan, among 245 athletes in this weight category.
He is also taller at 1.64m, while Toan is 1m58.
The Toan vs Amparo fight is part of the triple championship of the Thai Highland-Spaceplus Boxing Promotions.
Two other championship matches are between Muhammad Shoaib of Pakistan and Hendrik Barongsay from Indonesia. They will vie for the Asian Boxing Federation (ABF) lightweight (61kg) championship.
John Michael Zulueta of the Philippines will face Suriya Kraimanee of the hosts for the ABF light flyweight (49kg) belt.
Vo Hong Dat is matched up with experienced Vachayan Khamon of the hosts in the super lightweight (63.5kg) category.
Dat, 24, has recorded three wins from three in his pro career, all by KO.
He was also an outstanding boxer in his amateur career, winning silver at the National Boxing Championship in 2021.
Khamon, 45, has taken part in 48 matches. His record is 12 wins (4 KOs); one draw, and 35 losses (14 KOs).
Source: Vietnam News