While the five red cards handed out in a single Ligue 1 meeting between AC Ajaccio and SC Bastia in 2012-13 offers some insight into their direct history, events off the field involving the two Corsican clubs have often dominated the headlines too.

That stood as the most recent competitive meeting between the clubs until Bastia, demoted to the fifth tier in 2017 due to financial irregularities, sealed a third successive promotion last season to reach Ligue 2.

Eight years on from their last duel in the top flight, Bastia triumphed 2-0 as the derby made its long-awaited return in September.

On Saturday, the clubs meet for the reverse fixture in Ajaccio in a match which could have significant implications for both - at opposite ends of the table.

"The derby against Bastia is very important for the supporters because it is about regional supremacy," Ajaccio fan Anthony Tognetti tells BBC Sport.

"Outside of football, Ajaccio and Bastia have always been rivals. There is a strong antagonism between the two cities.

"The atmosphere between the ultras of the two clubs can be tense, especially during matches. Many incidents have occurred in the past and from now on the travel of supporters during the derbies is prohibited.

"For normal supporters, it is all about the bickering and 'macagna' - the jokes - around the matches."

Bastia defender Sebastien Squillaci's late goal in a 2-1 win confirmed Ajaccio's relegation from Ligue 1 in 2014

The rivalry geographically divides the rugged Mediterranean island of Corsica between its two main cities; the capital Ajaccio in the Corse-du-Sud department in the south-west and Bastia's Haute-Corse in the north-east.

"Bastia is seen as more natural, authentic Corsica compared to Ajaccio, which is more metropolitan," explains Corsican football journalist Thomas Andrei, a Bastia supporter.

"In a previous game when the Ajaccio fans travelled to Furiani, the Bastia supporters wrote a sign in graffiti saying 'welcome to Corsica', which obviously they didn't like.

"It does split the island."

Football on the 'Isle of Beauty' is inextricably tied to politics and the struggle for independence - indeed there are ongoing demonstrations

following the assault of a nationalist figure in a French prison - and matches against mainland teams are often heated.

Bastia in particular have a history of sanctions over supporter trouble. In 2014, 44 police officers were injured as violence marred a Ligue 1 match against Marseille, while in 2016 a police station was attacked amid clashes following a match at Reims.

Former France striker Thierry Henry recently said Bastia's Stade Armand-Cesari was the most intimidating place he played in during his 20-year career

Heading for relegation the next season, a match against Lyon had to be abandoned as home supporters twice invaded the pitch and one of the club's directors was banned for an altercation with the visitors' goalkeeper.

The club was also given a three-match stadium ban in 2017 after supporters racially abused Nice striker Mario Balotelli.

"To me, the Lyon match was the suicide of Bastia," added Andrei.

"Before that game the stadium was seen as a volcano - always close to erupting but it never actually did. That day, it finally erupted.

"It has calmed down since then but the support is still passionate. Football is passion in Corsica. Even when Bastia were relegated to the fifth division, there were 7,000 fans at a French Cup game."

On the field, it is Bastia who can claim the most success.

Winners of the 1981 French Cup, they also went close to European glory in 1978, losing a two-legged Uefa Cup final to PSV Eindhoven. They have spent 34 seasons in the French top flight in all, compared to Ajaccio's 13.

"Bastia is the historic club," says Didier Rey, a professor at the University of Corsica specialising in Corsican football. "It is considered by many to be the club that truly represents the Corsican people, the 'national' team of Corsica in a way.

"It has many more supporters than Ajaccio and you meet them all over Corsica, including Ajaccio. The opposite does not exist."

Bastia has also endured tragedy. In 1992, a temporary stand erected at the stadium to accommodate extra supporters for a French Cup semi-final against Marseille collapsed shortly before kick-off, killing 18 people and injuring more than 2,000.

As a show of respect, matches no longer take place on 5 May.

The French parliament passed a law banning professional football matches being played on the anniversary of the Furiani stadium disaster

Demoted to the amateur league due to financial irregularities in 2017, the Turcini (Blues) have recovered emphatically with three successive promotions.

This season they are 15th in the second tier, two points above the bottom three. In a tight relegation fight, six points separate the nine teams from 11th to 19th.

"On the side of the Ajacciens there is an inferiority complex towards the Bastiais because of their sporting past and what they represent in Corsica," said Rey.

"But the Bastia supporters today fear Ajaccio's sporting supremacy. They are afraid of being second to Ajaccio. This is also what makes the rivalry between supporters stronger."

It is Ajaccio who are close to ending a nine-year absence from Ligue 1 at last.

Ajaccio captain Yohann Cavalli attempted to speak to Le Havre's players after their team bus was damaged by Ajaccio supporters before their play-off match in 2018

Now in their eighth consecutive Ligue 2 campaign, L'Orsi Ribelli (the Rebel Bears) have been frustrated in their attempts to return to the top flight.

Four years ago, Ajaccio prevailed in a play-off against Le Havre, after the first leg had to be rearranged when Le Havre's team bus was attacked before kick-off, but missed out on promotion in a 4-0 aggregate final defeat by Toulouse.

They were also placed third, two points off the top, when the coronavirus pandemic led to the curtailment of the 2019-20 season.

Once again in third this season, Ajaccio are one point behind Paris FC in the final automatic promotion place, and six adrift of leaders Toulouse, with 11 games remaining.

"It would be an immense pride to win promotion to Ligue 1 and to be able to receive prestigious teams like Paris St-Germain or Marseille at Francois-Coty again," said Tognetti.

"Honestly, this year we believe it is possible because we have the mentality and the players for it."

While Olivier Pantaloni's Ajaccio and Regis Brouard's Bastia hold their own objectives on Saturday, both will no doubt be well aware of the influence they could yet have on the fate of the other.