It might have lost some of its old shine but Paris Saint-Germain against Lyon is still one of the biggest fixtures on the Ligue 1 calendar.

Les Gones have not been crowned Championnat kings since the last of their seven consecutive titles back in 2008 but they are still stronger than most opponents in the French top flight.

Considering Celtic's state in the wake of Tuesday's 5-0 thrashing in the opening round of Champions League Group B fixtures, Bruno Genesio's Lyon are arguably the strongest side PSG have faced so far this season -- certainly with Neymar and Kylian Mbappe both in the squad.

The Brazilian superstar and the French prodigy have really hit it off and both have two goals from as many appearances across Ligue 1 and the Champions League. The South American also has two assists to his name.

Celtic were a step up from FC Metz but Les Parisiens stuck five goals past each side and once again, Lyon are stronger than both of those teams and should provide the men from the capital with a sterner test at Parc des Princes.

Neymar and Mbappe will be expected to star once again, even if it was the third musketeer in Unai Emery's attack -- Edinson Cavani -- who truly stood out at Celtic Park earlier this week, and the Spaniard praised the developing chemistry between the two summer signings during Friday's prematch news conference.

"I think it is easier because of the quality they have," Emery told journalists when asked about Neymar and Mbappe's relationship. "That is why the players have settled well into the team. I think the team is good now and every game is a test to prove that.

"We have to continue to be strong and improve. We know that every team that comes to Parc des Princes, like Lyon this weekend, are going to cause us problems. This was already the case with Saint-Etienne in the last match.

"With players of this quality, I hope we will continue to play well. If we can keep showing progress, the whole team will benefit. For me, it is something that has to be worked on in each training session and in every single game."

Lyon at home and Montpellier away, particularly the former, must be used as opportunities for the Brazil, France and Uruguay internationals to continue to develop their understanding.

It is one thing putting five goals past limited outfits such as Metz and Celtic but it would be another to do it to Lyon and an even bigger achievement to be that prolific against a traditional European giant like Bayern Munich.

After two straight opening victories in Ligue 1, Lyon have stumbled a bit and have won just once in their last four outings -- 2-1 at home to Guingamp. However, with Nabil Fekir, Memphis Depay, Mariano Diaz and Bertrand Traore, this young team still possess the firepower to hurt PSG.

Defensive combinations of Thiago Silva, Marquinhos, Dani Alves, Layvin Kurzawa, Thomas Meunier, Presnel Kimpembe and Yuri Berchiche have looked vulnerable -- well, complacent -- against Toulouse and Metz, so if the back four Emery picks on Sunday is not as tight as it should be, Neymar, Mbappe and Cavani will be relied upon to outscore Lyon.

Kylian Mbappe, Neymar and Edinson Cavani have started promisingly at PSG. Franck Fife/AFP/Getty Images

Depending on whether the Basque tactician goes with the familiar possession-based 4-3-3 formation or the attack-minded 4-2-3-1 that is growing in popularity after Neymar and Mbappe's arrivals, this clash could be more of a test of PSG's midfield and defence than the attack.

However, regardless of how their teammates perform, Neymar, Mbappe and Cavani will be expected to continue to wreak havoc in front of goal and need to with Bayern approaching.

If Emery goes 4-2-3-1, which is likely with Adrien Rabiot struggling to be fit enough to start, Julian Draxler will probably be added to the equation with Angel Di Maria and Javier Pastore out and after the Germany international came on as a substitute to produce the fourth goal with a winding run and dangerous low cross in Glasgow in midweek.

Neymar and Mbappe need to continue to work on their understanding with Cavani and possibly Draxler too against Lyon and with next week's opponents Montpellier struggling, this will be the PSG attack's last real test before facing Bayern in Europe.

Ideally, the matches would have come the other way around but it is Lyon first. Neymar and Mbappe need to keep doing what they have done so far together and better their previous performance.

Judging by their first half against Celtic, Lyon's defence will have their work cut out for them on Sunday night in the capital.