Former Chelsea and Real Madrid man Claude Makelele steered Eupen to safety after an incredible last-day finale in Belgium's top flight.
Makelele, who worked as assistant coach to Carlo Ancelotti and Laurent Blanc at Paris Saint-Germain, was appointed in November with the mission of saving Eupen from relegation to Belgium's second tier.
Bottom of the table ahead of the final game, Eupen knew they needed to win against Mouscron by one more goal than rivals Mechelen, who started the day +1 better off in terms of goal difference. Eupen's superior goals scored tally meant they would stay up if points and goal difference were equal.
All hope for Makelele's men appeared to have evaporated with Mechelen leading 2-0 before the hour mark and Eupen goalless at the same stage in their encounter.
That meant Eupen needed to find the net three times to stay up, but incredibly they struck four in the final 17 minutes -- including a hat trick for Japanese forward Yuta Toyokawa -- to condemn Mechelen to the drop.
The nightmare turnaround in fortunes for Mechelen led their French forward Nicolas Verdier, who is on loan from Eupen, to criticise Mouscron, who finished third from bottom of the table but had already secured top flight survival before kick-off.
"From what I have heard, Mouscron did not respect the Jupiler Pro League. It's a lack of professionalism and a lack of respect that tarnishes the image of the club," he told Proximus 11. "We were leading 2-0 and Eupen score four in 20 minutes ... I hope there will be an analysis of incidents in the game and that decisions will be taken."
Belgian media reported prior to kick-off that the company charged with installing VAR for the game in Eupen had brought the wrong cables, meaning VAR could not be used.
Eupen will now contest the playoffs featuring the clubs that finished seventh to 15th in the 16-team league, and could qualify for next season's UEFA Europa League if successful.