Back in April, Laurent Blanc refused to acknowledge that the weekend’s match against 3rd-placed Nice was a tone-setter for Paris Saint-Germain’s first leg quarter-final with Manchester City, but despite some kind-hearted treatment of Hatem Ben Arfa in the first half, an imperious Zlatan Ibrahimovic inspired PSG to a simple 4-1 win. The Swede’s velvet touch was too much for the visitors to handle.

Runaway leaders PSG had already wrapped up the French league Ligue 1 in March with a 9-0 victory against bottom side Troyes, breaking the club record for league matches unbeaten (36). Fast forward to Sunday’s encounter between PSG and Nice and the fixture has a marked different context: Ben Arfa has swapped teams, Ibrahimovic has left for Manchester United, Blanc has made way for Unai Emery, and Nice are top of the table.

Nice’s remarkable surge has manifold roots: superficially, the inspired appointment of Lucien Favre as coach, together with the high-profile acquisitions of Mario Balotelli, Younes Belhanda and Dante were a trigger, but local business and club president Jean-Pierre Rivère also brought in Julien Fournier as chief executive.

Fournier implemented an overhaul of the club, emphasizing youth development and player scouting. He combined that with a specific sporting strategy. Former coach Claude Puel helped develop Nice’s new state-of-the-art training facility that will be inaugurated next year. Puel’s playing style was one of quick movements and short-passing. Under Favre, they have played eye-pleasing football.

For the outfit from the French capital, this season was always going to be transitional. Blanc could no longer match PSG’s ambitions. At home, there is nothing left for PSG to conquer. They are serial champions. At the same time they are in danger of becoming a lampoon: every European season is a neat, but frighteningly identical reproduction of the previous campaign, culminating in elimination in the quarterfinals.

In Europe, Blanc never convinced. He built a solid team around a nucleus of players – Thiago Silva in defense, Marco Verratti in midfield and Ibrahimovic up front, but PSG could never impose their possession-based game in the Champions League. Blanc became a victim of PSG’s obsession with the European Cup. He couldn’t take the Parisians any further.

Arriving in Paris, Emery had plenty of European pedigree, having won three Europa League trophies with Sevilla. His playing template is different from Blanc’s: he wants his team to play with more pressing and verticality, eradicating any possession indulgence that was an occasional feature of PSG under his predecessor.

But the players haven’t adapted smoothly to Emery’s plans. In midweek, PSG were strangely disconnected yet again against Bulgaria’s Ludogorets Razgrad. Silva and Marquinhos blundered at the back, Thiago Motta was cumbersome, Lucas faded after the break and Angel Di Maria was peripheral at best. They were incoherent. The 2-2 draw, on the back of a 3-0 domestic defeat to Montpellier, forfeited top spot in group A of the Champions League to Arsenal.

The tie with Nice represents a seminal moment in PSG’s season, because, as the halfway point of the season approaches, a crisis – in fact, if you got a moment, it would be a twelve-storey crisis with a magnificent entrance hall, carpeting throughout, 24-hour portage, and an enormous sign on the roof, saying ‘This Is a Large Crisis’ – is looming large. A defeat will result in a seven-point gap with the league leaders and, perhaps, the unravelling of PSG’s season and Emery’s future.

For the Spaniard, coaching PSG was never going to be easy. The Parisians still suffer from a mega-sized hole of 40 goals left by Ibrahimovic, the self-acclaimed Swedish god. The Swede thrived in a team that was largely built around him, even if he was not that mobile.

Ibrahimovic was often the get-out-of-jail player for PSG. It’s an additional puzzler for Emery – moving Cavani to the middle was never going to solve the problem, the match against Ludogorets a case in point when Cavani did not receive enough support. Often, the Uruguayan has been wasteful as well.

Nice are a benchmark for Emery and PSG – for once, they will be in a position of inferiority in the French League and the result will be telling of how much progress PSG have made this season. At least, they know that Ibrahimovic won’t be there to salvage the day – as he did when Nice last travelled to the Parc des Princes.