On Sunday, Lille OSC returns to the place where it clinched the Ligue 1 championship for the first time since 1954, amid joyous on-pitch scenes, back on May 21.

Paris Saint-Germain's big Sunday clash with the title holder (live, 3:00 p.m. ET, FOX Soccer Plus) at the Parc des Princes is as big as it gets in France at the moment, pitting the co-leader and title favorite against the team to beat.

Even if Lille is only in third place at the moment, two points from the summit, and though Montpellier holds first place from PSG on goal difference, the matter is clear in the minds of most - this is a clash of the two teams who will contest the title most doggedly.

Lille is on a club record run of 15 matches without defeat (nine wins and six draws), but probably arrives in the capital as second favorite. This is shaping up to be an epochal season in French soccer.

Antoine Kambouare is under more pressure to deliver results at big-spending PSG. (Photo by Jacques Brinon/AP Images)

Simply, PSG has turned Ligue 1 upside down. A perennial underachiever, it has been a club frequently lacking in structural stability in recent years and it was last champion in 1994. Current head coach Antoine Kombouare was a brusque defender in those days, in a side that included the likes of George Weah, David Ginola and former PSG and Lyon boss Paul Le Guen.

The huge investment by new majority shareholder Qatar Sports Investment (QSI) has threatened to catapult PSG way beyond the rest, with €87m ($108m) ploughed into recruiting a host of new players - over ten times the transfer budget of summer 2010.

It has also, however, turned Kombouare's world upside down. Having fostered a genuine locker room spirit and authored a drastic improvement on a difficult first year in charge, his PSG team pushed moneyed Lyon all the way for the third and final Champions League place, before eventually finishing fourth. The arrival of fellow former PSG player Leonardo has facilitated the arrival of a plethora of highly-paid stars that Kombouare has then been left to integrate into a previously close-knit team structure.

Star man: Javier Pastore wants the same sort of freedom he got when playing for Palermo. (Photo by Jacques Brinon/Getty Images)

The biggest of the buys, Javier Pastore, has required Kombouare to change tactics. A disciple of 4-4-2, he has switched to 4-2-3-1 to accommodate his star playmaker, yet still Pastore told this month's So Foot that he lacks the "freedom" that he would like. "At Palermo, I played as a real number 10," he lamented.

In between tactical and ego management, Kombouare has had to deal with constant speculation over his own position, with Leonardo casting a none-too-subtle eye over Europe for a haut de gamme replacement more befitting of the new, glitzy Paris. Talks have been held with Carlo Ancelotti and Rafael Benítez, but Kombouare has conducted himself with real grace in the situation, and carried on regardless.

Things have changed significantly for Lille since May too, with five of the 14 who participated at the Parc having left the club, including the key trio of Gervinho, Yohan Cabaye and Adil Rami. What has changed the most, though, is the northern club's stature. As league and cup double winner getting set to move into a stunning new 50,000-capacity stadium in 2012 (Grand Stade Lille Metropole), Lille is going places.

Joe Cole is loving his spell in France after turning down the chance to stay in England. (Photo by Vittorio Michel Spingler/AP Images)

The various replacements to those departed team members are testament to that. France winger Dimitri Payet rejected PSG because he preferred "the sporting project at Lille," and England international Joe Cole surprisingly rejected the chance to stay in the Premier League to join up. Cole admits being convinced by Rudi Garcia, whose creation of a 'mini-Barcelona', as they say in France, convinced the midfielder he could develop, even as he approached 30.

Of course, it could have been so different for Lille. The club fired Garcia in June 2009, after his first season at the helm, for disagreeing with director general Xavier Thuillot about the club's future direction and upsetting the long-serving - and influential - goalkeeper Gregory Malicki.

Rudi Garcia (right) has allowed Lille to play with more freedom than under Claude Puel's previous regime. (Photo by Michel Spingler/AP Images)

We can now say it was fortunate that fan power intervened, with a group of 200 protesting outside the club's offices on the back of several first-team players also questioning the decision. President Michel Seydoux changed his mind, brought Garcia back and fired Thuillot instead.

Like Kombouare, Garcia already had a playing pedigree with the club, and was a fan favorite. "I was here at LOSC for six good years as a player. I hope my tenure as coach can last at least that long," he told the media on his appointment in 2008. Whereas Kombouare relied on goodwill from his playing days to see him through a tough opening as coach, Garcia had no need to.

A sturdy, defensive outfit under Claude Puel before the head coach left for then-champion Lyon, Garcia liberated his players after coming in from Le Mans. A side previously admired for its obstinacy started to impress with its dazzle. Garcia's positive attitude has always flowed throughout his side and, despite the heavy financial advantage enjoyed by its host, arrives at the Parc on Sunday with its now-customary ambition intact.

"We're going to the Parc looking for the three points," defender Aurelien Chedjou told L'Equipe this week. "It will be difficult, as they have a very good team. But we have the capability - without being arrogant - to go there and get a result. We're going there to impose our game. His defensive colleague, France right-back Mathieu Debuchy, went a step further. "We have to win at the Parc des Princes," he told reporters after last week's win over Dijon.

Having suffered via administrative and sporting flux before, the powers that be at PSG would do well to take a leaf from Lille's book. Kombouare's team will present a formidable challenge for Garcia and company on Sunday - the season so far has been a case in point, with players of the high quality of Pastore, Kevin Gameiro and the in-form Jeremy Menez allowing the side to extract full reward for games in which they have only partially performed.

Yet in a week where both teams showed their greenness in Europe, Lille has the strength, stamina and guile to show it is in no mood to be pushed aside.