Vissai Ninh Binh, who quit the Vietnam top flight over a match-fixing scandal in the AFC Cup, took advantage of a slow moving investigation into the matter to book a place in last 16 of the tournament as Group G winners on Tuesday.
Earlier this month, 11 players of the Vietnam Cup winners told police they received around 800 million dong ($37,900) for fixing a March 18 AFC Cup match against Malaysia's Kelantan in which they came from 2-1 down to win 3-2.
The team were withdrawn from the Vietnam top flight amid fears domestic games could also have been fixed, but they were allowed to carry on their commitments in Asia's second tier continental competition.
Asked why Ninh Binh were granted the green light to continue, tournament organisers the Asian Football Confederation told Reuters they would wait for a "detailed investigation report from the Vietnam Football Federation (VFF) before AFC can take any action".
Further questions on the matter, which broke on April 11, went unanswered by the regional body, who have appeared slow to react to the latest in a long line of match-fixing scandals to hit one of their members.
Eight days after news broke, the AFC sent a "high level delegation" to the Southeast Asian nation to meet VFF officials and local law enforcement agencies on Saturday regarding the case.
On Tuesday, Ninh Binh, missing the players involved in the case and forced to play untested youngsters, thrashed Yangon United 4-1 away in Myanmar to secure top spot in the four team Group G of the AFC Cup.
"Some of them had little experience at this level but they took their chances well and I must praise their spirit and how well they performed because they did well in this big game," Ninh Binh coach Nguyen Van Sy told the AFC.
They will next face a home tie against either Singaporean side Home United or Churchill Brothers of India on May 13 - providing they are cleared to continue by the AFC after the investigation.
Chris Eaton, Director of Sport Integrity at the International Centre for Sport Security, said a revamp of procedures was required.
"Match-fixing investigations in sport need to be swift and effective and in the interests of sport and its credibility," the former FIFA head of security told Reuters on Wednesday.
"The difficulty in football is the mix of leagues, federations, regional federations, Confederations and at the global level, FIFA.
"Each have their responsibility, and each significantly crossover each other. In short, integrity investigations can be a confusion of responsibilities and actions.
"There is no collective football investigation and integrity mechanisms, which would certainly make the entire process faster and more definitive, the Vietnam investigation, police to League, League to Federation, Federation to Confederation and ultimately no doubt to FIFA, is just too slow."
AFC president Sheikh Salman Bin Ibrahim Al Khalifa said he planned to tackle the problem of match-fixing upon assuming office a year ago.
But the Bahraini has come in for criticism from fellow AFC member and FIFA vice president Prince Ali Bin Al Hussein of Jordan in recent weeks for spending too much time on politics and not enough on developing the sport in the region.
The way he chooses to tackle this issue in Southeast Asia, which Eaton has continued to say is the epicentre of the global problem, will be telling.
Vietnam Football Federation secretary general Lee Hoai Anh was confident, though, that any punishment would not extend to the country or its clubs being banned from competing in AFC competition.
"It is unlikely that Vietnam will face sanctions or any limits on its participation in Asian tournaments," he was quoted as saying by local media on Monday.
Eaton said he was in "no doubt" that a deeper connection than just the players was being investigated and again called for greater collaboration in order to tackle the fixers.
"Players are the tools. Investigations must go to the people who corrupted them and financed the fix," he said.
"There is a great deal to be done in all of football. The current global match-fixing scourge is doing enormous harm to the sport.
"The key collective bodies need to join together to form a universal, independent process to return the sport to public confidence. This is not an easy process, and the AFC is key to a new strategy.
"Football talks of zero tolerance and life bans, but ultimately this is the decision of independent tribunals."
(Editing by John O'Brien)